Conferenza e Edizioni

Volume 3 (2020): Edizione 1 (August 2020)

Volume 2 (2019): Edizione 2 (December 2019)

Volume 2 (2019): Edizione 1 (October 2019)

Volume 1 (2018): Edizione 1 (October 2018)

Conferenza Dettagli
Formato
Conferenza
eISSN
2545-2843
Pubblicato per la prima volta
30 Sep 2018
Periodo di pubblicazione
1 volta all'anno
Lingue
Inglese

Cerca

Volume 2 (2019): Edizione 1 (October 2019)

Conferenza Dettagli
Formato
Conferenza
eISSN
2545-2843
Pubblicato per la prima volta
30 Sep 2018
Periodo di pubblicazione
1 volta all'anno
Lingue
Inglese

Cerca

66 Articoli

Part 1: Modern Machines and Technologies for Mining, Editor: Krzysztof Kotwica

Accesso libero

Assessment of efficiency in reduction of dust concentration in mineral processing plants using the state-of-the-art technical measures

Pubblicato online: 07 Nov 2019
Pagine: 11 - 19

Astratto

Abstract

Airborne coal dust hazard at the workplaces in hard coal processing plants in Poland is presented. The methods for dust control in coal processing plants are discussed. The results from testing the dust control efficiency at the workplaces are given. The test results of airborne dust concentration are analysed as well as advantages and disadvantages of used technical measures are indicated.

Parole chiave

  • mechanical coal processing plant
  • coal dust
  • airborne dust control
  • dust removal
  • spraying
Accesso libero

Components of an innovative electro-control system for undeground mining – analysis

Pubblicato online: 07 Nov 2019
Pagine: 20 - 27

Astratto

Abstract

In the era of Industry 4.0, coal companies began to reach for new innovative technologies that increase work safety and their possible use affects the economic improvement of companies. One of them is to equip a powered roof support section with an electrohydraulic control system with a monitoring system that tracks operating parameters. The development of a monitoring system for a powered roof support is a key investment in new longwall complexes. It allows rapid diagnostics of status of the support. Currently used system designed to control the powered roof support are based on blocks of manually controlled distributors. The pilot control is currently the leading control that properly functions in all conditions, allowing to adapt to the requirements resulting from the construction of the section. A number of tests and analyses must be conducted prior to introducing the new control based on an innovative approach into operation. The basic research has focused on identifying the user interface that will potentially be the solution for the entire system. The user has defined how the driver should look like and how it will be operated and maintained. The results of the first series of tests on the elements of an innovative electronic control system of the powered roof support enabled to develop a prototype version. The assumptions for the system were verified during the conducted development studies. The article presents preliminary results of development research for devices included in the innovative control system of the powered roof support.

Parole chiave

  • fire hazards
  • powered roof support
  • natural hazard
  • nitrogen cushion
Accesso libero

Examples of vibratory crushers applications in crushing technological lines

Pubblicato online: 07 Nov 2019
Pagine: 28 - 36

Astratto

Abstract

Very fine crushing of hard and very hard materials, to product of particle size less than 2-4 mm at feed particle size of 50-200 mm, requires a very large energy inputs. This is mainly because of the need for at least three or even four degrees of crushing, containing: jaw, cone or impact crushers. One of the methods of reducing the amount of energy expended on the crushing process is reducing the number of crushers in technological line. By replacing a large number of less effective crushers with fewer machines but characterized by higher crushing efficiency we can gain considerable savings in investment and operating costs. This is possible by using crushers capable of obtaining much greater degrees of fragmentation than the aforementioned, that is vibratory crushers. The paper includes the systematic of currently used vibratory crushers, their mechanical diagrams, descriptions of the construction and operation, and basic technical parameters as well as examples of crushing technological lines utilizing vibratory crushers.

Parole chiave

  • crushing
  • vibratory crushing
  • vibratory crushers
Accesso libero

Determination of boom vibrations of the road header during cutting based on the analysis of images from high-speed cameras

Pubblicato online: 07 Nov 2019
Pagine: 37 - 49

Astratto

Abstract

Excavation, especially of hard rocks, using boom-type road headers is a source of strong vibrations of the boom in which they are equipped. These vibrations are transferred through construction nodes further to the turntable and the body of the road header. On the one hand, they are of great importance from the point of view of the durability and the reliability of the mining machine. On the other hand, they affect the variability of the parameters at which the process of cutting the heading face surface of a drilled roadway or tunnel is carried out. For the purpose of determining the vibration intensity of the boom of the road header a photogrammetry system based on two high-speed cameras Phantom Miro LC 120 was used. During the experimental investigations of the cutting process of a cement-sand block using the R-130 road header, the boom and turntable movements were recorded. The analysis of the time-lapse pictures of the recorded footage obtained from the high-speed cameras using dedicated TEMA 3D software allowed to determine the spatial trajectory of movement of the boom and the turntable during the cutting of the massive with specified mechanical properties with set values of the parameters of this process. Basing on the time courses of the coordinates of the boom and turntable characteristic points, the courses of the actual boom swinging speed and acceleration components of its vibrations were determined. The intensity of these vibrations was related to the conditions of the cutting process.

Parole chiave

  • road header
  • cutting process
  • vibrations
  • measurement
  • high-speed cameras
Accesso libero

Drilling and bolting rigs operator support using FGS (Feeder Guiding System) and remote control

Pubblicato online: 07 Nov 2019
Pagine: 50 - 58

Astratto

Abstract

The article presents the assumptions and main functionalities of two operator support systems – the FGS (Feeder Guiding System) and the remote control system of a drilling or bolting rig. Both of these systems greatly facilitate the work of an operator of a self-propelled mining vehicle in the conditions of an underground metal ore mine. The first of the described system allows for real-time control of the current position of the mining boom and facilitates the drilling of blast holes according to a predetermined drilling pattern. The second of the systems – a remote control system – is used especially in conditions of unstable rock mass or in the case of work in particularly difficult operating conditions, where it is advisable to limit the presence of the crew from the face-up to the necessary minimum. The intensity of these vibrations was related to the conditions of the cutting process.

Parole chiave

  • drilling rig
  • bolting rig
  • drilling control
  • remote control
  • drilling feeder system
Accesso libero

Methods of enlarging material to the concentration table

Pubblicato online: 07 Nov 2019
Pagine: 59 - 68

Astratto

Abstract

Concentration tables are one of the oldest oscillatory enrichments with over 100 years of tradition. On this type of distribution tables are made according to material mass in many recurring cycles induced by appropriate drives. So-called wet tables are the devices most often used for coal enrichment in Polish mines because this process generates very high costs, high water consumption and pollution of the environment, as well as the need for, among others, water and mud management is increasingly being replaced mainly in areas poor in water by the modern model of the air concentration table – FGX produced in China. The process of enrichment on this type of table itself runs in a manner comparable to the method of wet enrichment with the difference that the FGX is distributed on a perforated plate, in this case we deal with air pollution. Department of Machinery Engineering and Transport's attempts to use the differences in coefficients of friction in over-resonance screens have shown that it is possible effective separation of grains with different coefficients of friction. The article presents a theoretical analysis and presents the results of performed dry enrichment trials using different coefficients of friction. The summary presents the advantages of using the enrichment method using the differences in friction coefficients and test results.

Parole chiave

  • concentration table
  • coefficient of friction
  • enrichment
Accesso libero

Modified ground support with alternative fill material for ground control at munsar underground manganese mine of moil limited, India

Pubblicato online: 07 Nov 2019
Pagine: 69 - 77

Astratto

Abstract

MOIL Limited is operating 7 underground and 3 opencast mines in central India and producing annually more than 1.3 million tonnes of various grades of manganese ore. The underground mines are operating at shallow – 90 m at Munsar mine to moderate – 353 m at Balaghat mine below the surface with horizontal cut and fill (HCF) or its variant method of stoping with post filling by hydraulic sand stowing. The Munsar mine is being worked underground since 1903. The opencast mining is presently stopped. The ore body below the opencast quarry is geological continuity of the area excavated in past by opencast method of mining. The underground mining is done through the adit in three levels i.e. 270’L, 220’L, 170’L and by incline in western part of the property at 70’L. The horizontal drift development has been developed in the manganese ore body with sill drive of 5 m above the sill pillar in lower level at 70’L and barrier pillar of 5 m thickness is left for protection of upper level at 170’L. Valuable mineral has been locked in sill pillar and therefore rock mechanics investigations have been carried out. On the basis of study now the drift development has been carried out in footwall rock at 70’L, (-) 30’L and below levels and it has improved the minable manganese ore by about 20%. In this modified HCF stope design, an alternative fill material in place of sand, which has been developed in house by use of overburden (OB) material after treatment, has been used for hydraulic stowing. The experimental trials find out that the alternative fill material of OB is more compact and forms a non-expansion floor for the men and machines in the stope. This will certainly help in the introduction of mobile underground mining equipment for drilling in the stopes and mechanical mucking, transportation and loading of the ROM. The paper presents rock mechanics investigations and future use of alternative fill material of overburden material after heat treatment for better safety and productivity at Munsar Mine of MOIL.

Parole chiave

  • Cable Bolting
  • Heat Treatment
  • Overburden
  • RMR
  • Stowing
Accesso libero

Next generation technology for utilization of alumina rich iron ore tailings in India

Pubblicato online: 07 Nov 2019
Pagine: 78 - 85

Astratto

Abstract

Accumulation of low-grade iron ore tailings (IOTs) generated during the processing of high-grade iron ore has become a great threat to environment. Although wide range of research works has carried out to recover the iron values from the IOTs, but the solid recovery value has limited to ca. 50% in Indian context. In order to attain a maximum iron recovery and to utilize these solid wastes for future needs, an attention has shed on the topics of hydrometallurgy and applied nanomaterial synthesis from IOTs. Iron containing nanoparticles (ICNs) have huge potential in environmental and energy related applications. A wide range of synthesis methods has developed to produce ICNs from the mine waste. It is evident from the recent research works that converting waste materials into value added products are gaining more attentions. Objective of this review is to analyse the green synthesis routes to prepare ICNs from mine waste, starting from the physio chemical identification of waste material followed by discussion on various methods of ICNs synthesis routes from mine waste. It includes selective leaching method. Finally, the use of ICNs for environmental application had discussed in brief

Parole chiave

  • Iron ore tailings (IOTs)
  • Hydrometallurgy
  • Mineral processing
  • Iron containing nanoparticles (ICNs)
Accesso libero

Modern grinding balls sorting machines

Pubblicato online: 07 Nov 2019
Pagine: 86 - 95

Astratto

Abstract

Raw materials produced in large quantities are ground in ball, vibratory and stirred ball mills. In mills, the working parts are grinding balls. During grinding, grinding balls wear, change their diameter and lose their shape. The effect of this is the unfavourable change in the grinding balls parameters, which results in deterioration of the technological conditions of the milling process. Relevant parameters of the grinding balls set are restored during maintenance shutdowns. Grinding balls are sorted into appropriate size classes; grinding balls that are not suitable for further use are rejected, and then a set of grinding balls with appropriate parameters is used again. The time needed to prepare the required set depends mainly on the sorting time. To reduce this time, appropriate grinding balls sorting machines are used. The paper presents major problems associated with the grinding balls sorting process, a comparison of modern types of grinding balls sorting machines, a description of their construction and technological parameters.

Parole chiave

  • grinding media
  • grinding balls
  • sorting machine
  • sorting TAB
  • balls sorter
Accesso libero

Drive simulation tests for electric drilling rig

Pubblicato online: 07 Nov 2019
Pagine: 96 - 103

Astratto

Abstract

The article presents methodology and selected results of simulation tests of diesel and electric dive system for drilling rig. Research in this field were conducted under the project no. POIR.01.01.01-00-D011/16 entitled „New generation of modular rigs, drilling and bolting, with battery drives, designated to work in underground cooper ore and raw rock material mines”. The project is funded by the National Center of Research and Development (NCBiR). The aim of the project is to design and implementation of innovation drilling and bolting rig with electric drive system. Due to the complexity of the structure of the drive system (mechanical, hydraulic and electrical elements), it was necessary to use advanced simulation software dedicated to multiphysics analysis. Data presented in the article can be used as guidelines in design process of drilling and bolting rigs as well as in optimization their driving system and mechanical construction.

Parole chiave

  • drilling rig
  • bolting rig
  • electric drive system
  • dynamic simulation
Accesso libero

Innovative system for monitoring the tip over stability of mobile excavating machines on a tracked undercarriage

Pubblicato online: 07 Nov 2019
Pagine: 104 - 111

Astratto

Abstract

The article points out that the operational safety of mobile excavating machines can be significantly improved by equipping them with on-board systems for tip over stability monitoring. Critical analysis has been conducted on tip over stability monitoring systems available on the market. Their capabilities and limitations have been analysed. The second part of the article presents an innovative concept of on-board systems for monitoring tip over stability in tracked excavating machines. This concept was developed to create a device that would allow the vehicle's tip over stability to be monitored with greater accuracy and reliability compared to current systems of this type. The article also presents a demonstrator and a simulation model of the developed device. The final part of the article presents exemplary results obtained in preliminary simulation tests of the developed system.

Parole chiave

  • tip over stability
  • operator assisting system
  • monitoring system
  • mobile excavating machines
Accesso libero

Functional structure of battery drive for self-propelled mining rig used in room-pillar ore exploitation system

Pubblicato online: 07 Nov 2019
Pagine: 112 - 120

Astratto

Abstract

The article presents the structure of the battery drive of a self-propelled mining vehicle on the example of a drilling rig, used in the room-pillar system of copper ore exploitation. Such solutions, due to the ore mining in increasingly difficult operating conditions, are becoming more and more popular in the world. The main assumptions required for the synthesis of this type of drive were indicated, as well as the adopted structure of such a solution was described. The selection of the appropriate drive structure determines the final work characteristics of the self-propelled mining vehicle, and thus the actual suitability of such a machine for use in mining conditions. The paper also details the main technological advantages of this type of drive over classic internal combustion drives.

Parole chiave

  • drilling rig
  • bolting rig
  • battery drive
  • hard rock mining
  • electromobility
Accesso libero

Designing process of a toothed segment of the KOMTRACK haulage system

Pubblicato online: 07 Nov 2019
Pagine: 121 - 129

Astratto

Abstract

The following stages of a designing process of the toothed haulage segment are presented in the article. The toothed segment, developed within the framework of the KOMTRACK project, is an element of an innovative haulage system for highly productive longwall complexes. The project, according to the Contract No. POIR.04.01.04-00-0068/17, realized by the consortium: KOMAG, AGH University of Science and Technology, Foundry Institute, Specodlew Innovative Enterprise of Foundry Engineering, Ltd. and Polish Mining Group, J.S.C., is co-financed with the means of the European Regional Development Fund. The toothed bar, made of toothed segments of the haulage system, works together with the track wheel of a shearer haulage unit. A distinguishing feature of the newly designed haulage system, in relation to the system used at present, is its flexibility enabling individual toothed segments to adapt to longitudinal and transverse curvatures of the longwall conveyor track, which guarantees a correct cooperation with the track wheel.

Parole chiave

  • longwall system
  • shearer
  • shearer haulage system
  • toothed segment
  • gear wheel
Accesso libero

Ageing Process of Hydraulic Oil in Single-Bucket Excavators in Rock Mining

Pubblicato online: 07 Nov 2019
Pagine: 130 - 139

Astratto

Abstract

The paper presents the problem of ageing processes of hydraulic oils when used in single-bucket excavators in mining of rock raw materials. Working parameters of these excavators are specific, particularly when a hydraulic hammer is mounted in place of the working bucket, therefore the course of the oil degradation process and the change times should be precisely determined as full functionality of hydraulic systems of excavators must be maintained and the wear of individual components of these systems should be reduced. Research on oil ageing processes has been carried out for excavators from various manufacturers that have operated in mines of rock raw materials of various raw material extraction quantities. The methodology adopted for testing the ageing processes of oils in excavators allowed to obtain a number of results that question the hitherto applied criteria for quality assessment of used oils in relation to the time of their actual use in hydraulic systems of excavators, as well as the time of change of such oils.

Parole chiave

  • single-bucket excavators
  • hydraulic oil
  • oil ageing process
  • quality testing of hydraulic oil
Accesso libero

Experimental identification of the impact of sectional satellite wheels on the load distribution in the meshing of the planetary gear in mining machines

Pubblicato online: 07 Nov 2019
Pagine: 143 - 152

Astratto

Abstract

This article attempts to solve the problem of load compensation in mesh planetary gearing, with the innovative design idea, resulting from the increased plasticity of the planet wheels (satellite). The cognitive main objective of the experimental work was carried out to identify the comparative effect of the split narrow planet gears, on the load distribution on the length of the teeth of the planet gears of the central wheel of the planetary gear. Achieving this aim, in addition to in-depth analysis, requires experimental research on a specially-built test stand and simulation tests on a solid model of the transmission using the finite element method (FEA). This article presents the concept of a novel test stand, design methodology and research on the influence of the sectional satellite wheels on the load mesh of planetary gears in mining machines.

Parole chiave

  • drive system
  • planetary gear
  • load condition
  • design methodology
Accesso libero

Simulation of the frequency response of the ERC 1400 Bucket Wheel Excavator boom, during the excavation process

Pubblicato online: 07 Nov 2019
Pagine: 153 - 167

Astratto

Abstract

The paper deals with the modal analysis and frequency response analysis of a bucket wheel excavator (BWE) boom, obtained by simulation, based on a virtual model of an existing BWE boom. The boom, which generally is realized as a spatial truss, is the most vulnerable subsystem of the BWE, being submitted to severe operational loads characterized by very pronounced cyclical, dynamic and stochastic variability. This vulnerability is the consequence of its shape and constructive parameters and the nature, source and character of the external exciting loads to which it is exposed. The classical approach recommended by standards and norms cannot predict the occurrence of failures caused by vibration, which produces fatigue due to the load’s cyclical variability and the deformation produced by resonant vibration of some constitutive elements. As exciting load we considered the operational forces acting on the bucket wheel. In this manner we can take into account the constructive features – with modal analysis, and the vibration regime – with frequency response analysis. The proposed method is useful both in the design phase of new load-bearing structures of truss type subjected to high-variability forces, and also in refurbishment or improvement phases of the existing structures of this kind.

Parole chiave

  • Bucket wheel excavator
  • damping
  • frequency response
  • modal analysis
  • resonance
Accesso libero

The use of flat steel-polymer supporting ropes in mining multi-pole hoisting devices

Pubblicato online: 07 Nov 2019
Pagine: 168 - 177

Astratto

Abstract

The paper presents the development of a series of flat steel and polymer bearing ropes using a polyurethane polymeric material (the name of NPSP – flat steel-polyurethane). These ropes are intended for mining extraction devices with friction drive (multi-mill drive wheel, multi-rope drums with a number of ropes from 3 to 12 pieces). The authors of this article have presented a comparison of the drive power of a selected multi-mine mine hoist device with a classic steel round rope with the same extractor in which steel and polymer flat carrying ropes were used. The article also presents the development of mining construction of hoisting equipment, which includes the use of new rope ropes. Very positive results from exploitation in Polish mining of flat steel-rubber balance ropes (durability up to 12 years) can be the basis for the use of such ropes as supporting ropes. Flat steel-polymer supporting ropes, in which the matrix can be rubber or polyurethane or other plastic material, could contribute to increasing the durability of load-bearing ropes due to anti-corrosion protection as well as to reduce the dimensions of drive wheels and rope hoisting machines, and thus to lower the power of the winding machine (as a result of reducing the moments of inertia of the propeller, propulsion and rope). It is also worth mentioning that the NPSP carrying ropes can work directly on steel coatings of propeller drums with proper positioning, created by clamping elements (wood, plastic or aluminum blocks).

Parole chiave

  • ropes
  • flat
  • polymer
  • polyurethane
Accesso libero

Fem stress analysis of a barrel reamer

Pubblicato online: 07 Nov 2019
Pagine: 178 - 185

Astratto

Abstract

Horizontal Directional Drilling (HDD) is a method of installing underground pipelines, cables and service conduit through trenchless methods. The tools and techniques used in the HDD process are an outgrowth of the oil well drilling industry, too. Installation of a pipeline by HDD is a three stages process. The first stage consists of directionally drilling a small diameter pilot hole along a designed directional path. Drilling fluid is pumped through the drill pipe to the drill bit where high pressure jets and the bit will grind the soils ahead of the drill stem. The second stage involves enlarging this pilot hole to a diameter suitable for installation of the pipeline. A reamer is pulled back and rotated while pumping drilling fluid to cut and remove solids to enlarge the hole. A kind of reamer is the subject of this paper. The final stage consists of pulling the pipeline back into the pre-reamed hole. The most important part of the mechanical analysis is to define the boundary conditions for operating situations when the tool is under maximum load. In this paper we present a helpful description for giving boundary conditions to perform the numerical simulation of a barrel reamer.

Parole chiave

  • HDD technology
  • reamer
  • FEM
  • stress
  • displacement
Accesso libero

The new method for assessing rock abrasivity in terms of wear of conical picks

Pubblicato online: 07 Nov 2019
Pagine: 186 - 194

Astratto

Abstract

During the exploitation of mineral raw materials, a cutting tool is an element that is directly in contact with the unmined stone being cut. The most commonly used cutting tools include conical picks. The increasing pressure to reduce mining costs causes an increasing demand for affordable and reliable ways to increase the reliability of mining machines. Abrasive wear is the most common process affecting the wear of shearer picks, hence a good and simple laboratory method for assessing rocks abrasivity is needed. The new method was developed in the aspect of selection of conical picks with appropriate protection of the pick working part, increasing its durability. The method involves the assessment of mass abrasive wear of a standard steel pin and rock sample, and the determination of the abrasivity index Wz of the tested rock, as the ratio of the mass loss of the steel pin to the mass loss of the rock sample. The article presents the procedure of conducting tests, construction of a laboratory test stand and the use of the developed method to assess the abrasivity of gangue rocks occurring in the currently cut tunnel excavations of Polish hard coal mines.

Parole chiave

  • test method
  • assessment of abrasivity
  • conical picks
  • abrasive wear
  • underground mining
Accesso libero

An attempt to increase technological capabilities of laboratory vibratory mills by changing the construction of chamber

Pubblicato online: 07 Nov 2019
Pagine: 195 - 205

Astratto

Abstract

The paper presents the issues related to the grinding process in the vibration mills with low vibration frequency. These mills are rated among devices with high energy of impacts with much wider potential of industrial use than the classic gravitation mills. In vibratory mills there is an unfavorable decrease in the intensity of the grinding process along with the increase in the chamber diameter, which makes it impossible to achieve high performance of such devices. One of the ways to reduce or eliminate this occurrence is to intensify the load movement inside the chamber – this is the subject of this article. The article shows that in a vibrating mill of periodic action it is possible to increase its technological capabilities by application of an appropriate cylindrical component permanently installed inside the milling chamber. The paper also presents an attempt to increase the technological capabilities of a laboratory continuous vibratory mill.

Parole chiave

  • mills
  • vibratory mills
  • fine grinding
  • high energy mills
Accesso libero

Study of the efficiency of the large-diameter fishing tools with the moving magnetic systems

Pubblicato online: 07 Nov 2019
Pagine: 206 - 213

Astratto

Abstract

The variety of accidents which happen during the construction of oil and gas wells causes the expansion in the use of magnetic fishing tools. However, the known tools based on permanent magnets have a significant drawback involving the flat working surface of the magnetic system that does not permit to achieve a considerable attraction force to a fished object of complex geometric shape. Therefore, the aim of the research is to increase the efficiency of removalthe objects of irregular geometric shape from the wells by enlarging the area of contacting them. For that purpose, it has been developed a fundamentally new design of the large-diameter fishing tool with the moving magnetic systems capable of copying the shape of the objects to be fished. Each magnetic system, which is compound of permanent rare-earth neodymium magnets and concentrically placed magnetic cores, shall be held by the magnetic field of adjacent systems with opposite polarity. There were conducted theoretical studies using the finite element method to determine the working capacity of the designed tool. As a result, it has been found the valueof hoisting capacity during the interaction of magnetic systems with the roller cone of the drill bit; this fact confirms the capability of fishing the objects of irregular geometric shape. In addition, it has been explored the influence of the material of the fished object on the power characteristics of magnetic systems. The application of the designed magnetic tool allowsremoving the ferromagnetic objects from the well regardless of their shape, weight and position onthe bottom hole. Apart from that, the given tool may be used in the areas where the technology of work is related to drilling wells.

Parole chiave

  • fishing tool
  • magnetic system
  • permanent magnet
  • hoisting capacity
Accesso libero

Modified calculation model for loads of bearing systems for tricone roller bits

Pubblicato online: 07 Nov 2019
Pagine: 214 - 222

Astratto

Abstract

The article presents a modified calculation model of loads of cone bearing systems in tricone roller bits. The presented model includes the actual nature of the loads of a tricone roller bit and the effect of these loads on the construction of individual elements of the cone bearing systems. The presented calculation model was created in order to develop a computer program that allows the calculation and verification of structural parameters of cone bearing systems even at the stage of their initial design. It will allow an optimal selection of these parameters to geological properties of drilled rocks.

Parole chiave

  • drilling
  • drilling tools
  • tricone roller bit
  • cone bearings reaction calculation
Accesso libero

Asymmetrical mini disk tools – possibilities of use and directions for further development

Pubblicato online: 07 Nov 2019
Pagine: 223 - 232

Astratto

Abstract

The paper presents a new solution of asymmetrical mini disk tools for mining head of roadheader designed for hard and very hard rock mining. In the first part the benefits of disk tools used in TBM's and special tunneling machines were presented. Next part presents the results of works and laboratory tests performed for developing of new solution of asymmetrical mini disk tools. On the basis of these results new mining head equipped with mini disk tools with a complex trajectory was designed. The results of field tests with different constructional and material solutions of asymmetrical mini disk tools were presented. The directions for further development were described.

Parole chiave

  • hard rock
  • mechanical mining
  • disk tool
  • tool wear
  • efficiency
Accesso libero

Vibration analysis of a bucket wheel excavator boom using rayleigh’s damping model

Pubblicato online: 07 Nov 2019
Pagine: 233 - 241

Astratto

Abstract

For the ERc 1400-30/7 type bucket wheel excavator (BWE) used in various Romanian open pit mines, a virtual model of the boom was constructed in SolidWorks. On this model, the variable in time forces acting during the excavation process were simulated, and the time history analysis (time response) was performed. This dynamic time response analysis was performed for excavation of homogenous material only, considering the damping as being of Rayleigh’s type, where the damping matrix is a linear combination of the mass and stiffness matrices. Based on the conducted analysis, the displacements of the boom during excavation were observed.

Parole chiave

  • Bucket wheel excavator
  • damping
  • frequency response
  • modal analysis
  • resonance
Accesso libero

The influence of belt cover thickness on conveyor belt indentation rolling resistance

Pubblicato online: 07 Nov 2019
Pagine: 242 - 248

Astratto

Abstract

One of the methods for lowering of energy consumption in the drive mechanisms of long horizontal belt conveyors is to reduce belt indentation rolling resistances. These resistances depend on a number of factors: bottom cover properties, bottom cover thickness, belt design, idler diameter, load, speed and frequency at which the belt passes on the idler (indentation frequency), as well as on temperature. Determining how these factors influence indentation rolling resistances of various conveyor belt types is of great importance. The article describes a small-scale method for testing indentation rolling resistance. The method allows analysis of the influence of various factors on indentation rolling resistances. The article presents the results of tests on how belt indentation rolling resistance is influenced by thickness of the belt bottom cover. The tests were performed on belts with various core types.

Parole chiave

  • belt conveyors
  • conveyor belt
  • indentation rolling resistance
Accesso libero

Impact of selected parameters on the loading process with cutting screw heads

Pubblicato online: 07 Nov 2019
Pagine: 249 - 256

Astratto

Abstract

The article presents the influence of selected constructional and kinematic parameters of cutting screw heads on the loading process. The loading process is often referred to as an auxiliary process, because in the entire operation of the head the cutting process is considered dominant. Proper determination of the relationship between the cutting process and the loading process allows to understand how individual constructional and kinematic parameters of cutting heads and the cutting machine on which they are installed have an impact on each other. This knowledge gives potential users an opportunity to determine a reason for the lack of effective loading in the working conditions of a given wall. Besides construction and kinematic parameters, shielded loaders also have an impact on the loading process. The use of a shielded loader allows for improving the efficiency of the loading process, i.e. increasing the percentage of output loaded in the whole of the output transferred by the head.

Parole chiave

  • longwall shearer
  • loading of output
  • cutting screw head
Accesso libero

Supporting problems at an island mining face in shanxi, China. Case study based on field observation

Pubblicato online: 07 Nov 2019
Pagine: 257 - 267

Astratto

Abstract

In this paper, field observation is conducted in Fujiaao Coal Mine, Linfen city in Shanxi province, China, which is unique because of its island-typed mining layout. Firstly, geology, layout of the coal cutting face, supporting pattern are presented and details are also provided. Then the problems are discussed and analyzed based on existing bolting theories. It finds out the length of the cable bolt is too long, which requires long time to drill boreholes, whilst the effectiveness is limited due to the illogical combination between cable bolt function zone and rock bolt function zone. Also, the face place allocated to rock bolt is very likely to cause line contact between its edge and steel belt, thus the bearing force is tremendously weakened and solely determined by strength of belt. Furthermore, field observation proves the low active supporting effects to roof, thus leading obvious roof sink even without the disturbance of mining activity. Eventually, some solutions are proposed with the intention to improve the situation based on the economic and technical considerations, including bolting in humidity environment, rational cable bolt length, wise choice of face plate, and ways to increase pretension force. The viewpoints and comments of this study can be referred by practitioners in coal mines sharing same difficulties.

Parole chiave

  • coal mine support
  • bolt
  • support optimization
  • field observation
  • support failure
Accesso libero

Analytical investigations of the accuracy of the small diameter tool-joint tapered thread made by a lathe machining

Pubblicato online: 07 Nov 2019
Pagine: 268 - 276

Astratto

Abstract

The drill string consists of connected drill pipes and other elements. The connection is carried out by screwing of the drill string elements with the help of tool-joint tapered thread. The operational characteristics of the drill pipes depend of the manufacture precision of these tool-joints mostly. The accuracy of the thread is regulated by the accuracy of its profile and the accuracy of its pitch diameter value. The accuracy of the tapered thread manufacturing on the lathe in its depending on the values of the geometric parameters of the lathe tool and the values of deviations of its installation relatively to the workpiece axis is investigated. It is proved that for the tapered thread of form VI profile used for connection of drill pipes with the diameter from 30 mm to 44 mm the most influential factor, in relation to the accuracy of the thread profile is the value of the rake angle. Application of the rake angle value up to −5° according to the research data leads to a deviation from the specified profile of 0.3°, which is more than 35% of the declared standard tolerance on deviations from the profile. Also, the influence of the back rake angle value on the value of the deviation from the standard pitch diameter of the thread is proved. It is proved that the magnitude of the tangential displacement of the nose of the cutter relatively to the axis of the thread up to −0.2 mm can cause a deviation of the profile angle of 0.18°, which is 27% of the standard tolerance.

Parole chiave

  • drill string
  • back rake angle
  • tool-joint tapered thread
  • pitch diameter
  • lathe tool
Accesso libero

Directions for increasing conical picks’ durability

Pubblicato online: 07 Nov 2019
Pagine: 277 - 286

Astratto

Abstract

Conical picks are cutting tools used in many branches, in particular in the mining, road construction and building branch. Contact with the excavated face causes their constant wear, which is an unfavorable but unavoidable process. Milling heads of working machines are equipped with several dozen conical picks, and mining in abrasive or hardly accessible rocks can reduce their life to a few hours. It is in the interest of both users and producers to increase their durability, as tools replacement, apart from purchase and logistic costs, results in machine downtimes. In the article various solutions of conical picks, their construction, dimensions and materials used have been discussed. Technical procedures applied to increase the durability of conical picks and their regeneration as well as methods of extending the life of picks working in difficult conditions have been presented. Two author’s methods of extending the life of picks working in difficult conditions, covered by a patent application, have also been presented. The first solution involves ensuring an uninterrupted rotational movement of the pick in the holder. Patent claims include an innovative method of equipping the additional sleeve integrated with the holder with a rotational bearing, which enables a continuous rotation of the pick. The tool equipped with a bearing generates much lower movement resistance than the standard mounting. The holder is designed to mount classic commercial picks. What is important, the pick replacement does not require interfering with the bearing assembly. The second solution concerns the manner of protecting the working part of the pick by means of a special element made of an abrasion resisting material. This element is the pick tip, the geometry of which varies from the commonly applied posts made of sintered carbide. In this solution, the tip has a shape corresponding to the form of conical pick’s wear, which causes that its steel body does not wear. Moreover, there is a possibility of applying a mobile, rotational mounting of the tip to the body.

Parole chiave

  • conical picks
  • durability of tools
  • tool wear rate
  • pick equipped with a bearing
  • innovative solutions
Accesso libero

Determination of crushing energy during vibratory crushing

Pubblicato online: 07 Nov 2019
Pagine: 287 - 294

Astratto

Abstract

The paper presents a new method of determining the energy consumption for vibratory crushing. Using the laboratory vibratory jaw crusher with kinematic actuation of the jaws, the study of determining power consumption while crushing limestone and diabase was conducted. During the study, electrical energy used on the crushing process was measured as a function of changing design and kinematic parameters of the vibratory crusher, i.e.: jaws stroke, the outlet gap size and frequency of jaws vibration. The article presents program of the research, the laboratory test stand of the vibratory jaw crusher KW 40/1 and the test results. Comparing the theoretical crushing energy requirements, determined by the Bond hypothesis, with the values measured during tests a large differences were observed. Using the Bond hypothesis the Vibratory Work Indexes were determined for the tested materials. Their values are higher than limestone and diabase Work Indexes available in the known literatures. The explanation may be greater amount of energy transferred to the material during vibratory crushing, which results in much higher efficiency of the crushing process.

Parole chiave

  • crushing
  • vibratory crushing
  • crushing energy
Accesso libero

The use of simulation modeling in the design of elements of annular preventers

Pubblicato online: 07 Nov 2019
Pagine: 295 - 303

Astratto

Abstract

One of the main elements of control over wells in the process of their construction is the blowout equipment, which includes annular preventers. This also applies to wells that provide degassing of coal veins to reduce their gas dynamic activity. Modern technology of work requires expansion of the functionality of the sealing unit of the annular preventers with the simultaneous provision of its operational characteristics. Determining the necessary durability of seals for different operating modes is the study of their stress-strain state. The paper deals with the possibility of using simulation modeling in the annular preventers design situations and within the study of the armature geometry influence of the sealant fittings on its stress-strain state. The method of determining the material constants to realize the Mooney-Rivlin model has been proposed. The behavior of low-density rubber in software product has been described by the finite element method. The aggregation error of experimental and theoretical studies is 5%. Therefore, the preconditions and the possibility of using simulation modeling in the design of annular preventers devices with increased operational characteristics have been created and confirmed.

Parole chiave

  • simulation modelling
  • stress-strain state
  • annular preventer
Accesso libero

Modeling the movement of broadcast on the concentration table

Pubblicato online: 07 Nov 2019
Pagine: 304 - 311

Astratto

Abstract

The article attempts to analyze the work of the concentration table, on which the distribution of the material under investigation takes place. The efficiency of separation or otherwise enrichment depends on the drive that puts the concentration table plate into an asymmetrical reciprocating movement. The most frequently used solutions are concentration tables, on which the distribution of enriched material takes place in an aqueous medium commonly called wet enrichment. The AGH University of Science and Technology conducted simulation tests of material enrichment on a concentration table using the differences in friction coefficient commonly referred to as dry enrichment, i.e. without an additional medium. The article presents the effects of simulations that have been carried out for reference materials characterized by different friction coefficients and densities. The summary presents the analysis of obtained effects of computer simulations of material movement with different coefficients of friction. The simulations were carried out for variables: the frequency of vibrations of the concentration table and the angle of inclination of the table of the concentration table. It has been shown that it is possible to enrich the material by changing the above-mentioned operating parameters of the device.

Parole chiave

  • concentration table
  • coefficient of friction
  • enrichment
Accesso libero

Steel ropes in machines opencast mining

Pubblicato online: 07 Nov 2019
Pagine: 312 - 320

Astratto

Abstract

Basic opencast mining machines belong to the group of devices used to perform specific technological operations through mining, loading, transport up to the dumping of mining heaps. Machines work in EBD systems (Excavator-Belt-Dumping) and require high reliability. Multi-bucket excavators that require the use of rope systems in order to maintain stability and the possibility of mining at different levels. The paper focuses on issues related to rope work in multi-buckets excavators. On the basis of studies to assess the technical condition of the ropes identifies the causes of damage to ropes these machines. As a result of the research, final conclusions were formulated.

Parole chiave

  • wire rope
  • opencast mining
  • rope damage
Accesso libero

Small-scale testing of coal dust explosion propagation and relation to active barrier suppression systems

Pubblicato online: 07 Nov 2019
Pagine: 321 - 329

Astratto

Abstract

Coal dust explosions are a lethal threat to anyone working in an underground coal mine. Many coal mining countries including Australia and much of Europe already utilize passive barrier explosion suppressant systems but due to differences in ventilation patterns in the United States, simple passive systems such as the bagged barrier are not as cost effective. Active systems are triggered by properties of an explosion, such as pressure, heat, or light, and release or project a suppressant into the environment to suppress an explosion. To deploy an active system, the best sensor and suppressant release location and spacing must be determined; this must account for total system latency and explosive propagation speed. A 10:1 model of a longwall entry system has been developed to study the pressure wave propagation of coal dust explosions and consequent triggering of different suppressants. The scaled model, with its removable stoppings, allows multiple potential propagation pathways for an explosion to be repeatedly tested, different from typical straight shock tunnel tests. The layout also facilitates the placement of sensors and cameras to fully observe and document the tests. The pressure wave characteristics found at crosscuts and corners will aid in the development of active barrier trigger systems and spacing of suppressant release locations.

Parole chiave

  • coal dust
  • explosion
  • mine
  • active barrier
Accesso libero

Application of friction braking devices in drum shaft hoists

Pubblicato online: 07 Nov 2019
Pagine: 330 - 336

Astratto

Abstract

This article presents the problem of emergency braking in mining shaft hoists equipped with drum. The industrial applications of friction devices and mobile fender beams concerned only friction shaft hoists. For drum devices, it is necessary to use braking devices both in the shaft tower and its sump. The impact of such a solution on the construction of braking devices and on the braking process itself is the subject of the paper.

Parole chiave

  • shaft hoists
  • emergency braking
  • mobile fender beams
Accesso libero

The methodology of testing rotational resistances of the rollers under the operation load

Pubblicato online: 07 Nov 2019
Pagine: 337 - 343

Astratto

Abstract

One of the components that affects the energy consumption of belt conveyors is the rotational resistance of the rollers. In real conditions, the roller is subjected to loads not only radial but also axial, resulting from its cooperation with the belt and the way of installation on the conveyor. Knowledge of these resistances is important not only in the design of conveyors, but also in the improvement and search for new structural solutions of the rollers. The article presents an innovative stand dedicated to the study of rotational resistance of the rollers under operating load, its research capabilities and the results of preliminary tests.

Parole chiave

  • belt conveyor
  • roller
  • rotational resistances
  • operation load
Accesso libero

Systems of grained materials automated sampling from belt conveyors

Pubblicato online: 07 Nov 2019
Pagine: 344 - 352

Astratto

Abstract

The collection of representative samples of grained materials is necessary to determine the quality parameters of this material. This operation is carried out in difficult conditions (dustiness, noise, atmospheric precipitation), which is a nuisance to the staff taking samples and adversely affects accuracy. In addition, the quality of representative samples is affected by the care of personnel. Therefore, to ensure a higher quality of sampling operations and to eliminate the work of people in difficult conditions, systems have been developed for the automatic collection of representative samples from conveyor belts. The work gives examples of automatic sampling systems equipped with samplers and other auxiliary devices. The work contains descriptions of construction, classifications, an example of selection and examples of construction solutions for automatic sampling of grained materials.

Parole chiave

  • grained materials samplers
  • sample preparing
  • automated systems
Accesso libero

Equipment/machinery failure rate in hard coal mines

Pubblicato online: 07 Nov 2019
Pagine: 353 - 363

Astratto

Abstract

The main task of the maintenance services in hard coal mines is to ensure continuous operation of the equipment (machines). The measurable effect of these actions should be the reduction of maintenance costs of equipment (machinery) and thus the reduction of production costs – coal mining. The paper presents an issue of failure rate of technical measures applied in the mining process. In order to ensure greater efficiency and productivity, it is necessary to find the causes of the most frequent failures in this process and effectively counteract them. As a result of these activities, the production availability of machines/equipment involved in the mining process will increase. This will to a large extent ensure failure-free and uninterrupted progress, increase productivity and improve the quality of manufactured products, as well as reduce the operating costs of equipment (machines), and thus reduce production and product costs. This effect should consist mainly in the control of rational, safe and effective use and operation of equipment (machines) in the exploitation process. An algorithm implemented in one of the hard coal mines was presented. The technical condition of underground mining equipment was observed by periodical measurements of vibration parameters at selected points on the machine – measurements were conducted with a vibration pen. The aim of this research is to improve the reliability of technological process of a mining plant through its failure-free operation. In order to achieve this objective, i.e. the efficiency of a mining company, it is necessary to reduce its costs. The action that leads to this aim is a proper assessment of the technical condition with regard to the equipment used in technological process.

Parole chiave

  • mining machinery/equipment
  • failures
  • vibration pen
  • measurements

Part 2: Selected Organizational Problems in the Mining Industry, Editor: Krzysztof Kotwica

Accesso libero

Research on the coefficient of friction of becorit K22 and K25SB linings

Pubblicato online: 07 Nov 2019
Pagine: 367 - 375

Astratto

Abstract

The article presents the method and results of experimental tests of the coefficient of friction between a steel rope and friction lining. The BECORIT K22 and BECORIT K25SB floor coverings were tested. The tests were carried out in accordance with the recommendations of the new German standard: DIN 21258 – Lubricants and impregnating agents for drive discs and transport ropes in mining – safety and testing requirements. The authors in this article emphasize that the Becorit K22 and K25SB linings are used for the wheels of propeller drums of mining machines. Characterized by high coefficients of friction (μ ≥ 0.25), also in cases of extreme weather conditions on the surface. The chemical properties of BECORIT linings ensure their resistance to swelling in the event of different oils and lubricants as well as mine waters. The material of which the claddings are made ensures very good machinability during rolling of rope grooves with the use of turning or milling tools. BECORIT K22 plastic cladding is particularly suitable for use in hoisting machines, where the rope base forms a large overlap angle on the wheel grooves (max 1°31'), which causes its lateral wear faster. BECORIT K22 material in this case provides a higher service life compared to other materials. Due to the way they are mounted on the wheel, they are made as 1-piece (monolith) or bipartite. In this article, moreover, the structure and principle of operation of the measuring station on which the tests were carried out are presented in great detail.

Parole chiave

  • steel rope
  • coefficient of friction
  • lining
Accesso libero

The history of mining and metallurgy of metal ores in upper Silesia preserved in metallurgical waste dumps

Pubblicato online: 07 Nov 2019
Pagine: 376 - 383

Astratto

Abstract

The history of mining and metallurgy in Upper Silesia dates back to the early Middle Ages. Initially, appearing on the surface, calamine, i.e. oxidized zinc-lead ores, and limonite – iron ore were used. The development of mining technology allowed for exploitation of ore deposits at greater depths. It contributed to the intensive development of industry at the turn of the 19th and 20th centuries. At that time, one of the most important industrial settlements was today's Ruda Śląska. In its area, apart from hard coal mines, there were several forges processing locally exploited zinc, lead and iron ore. The testimony of the former mining and metallurgy, among others, is the dump, which is a remnant of the Hugo zinc smelter (1812-1932). Mineralogical and chemical analyzes of waste material collected on the dumping ground provide a lot of interesting information about the processed raw material.

Parole chiave

  • metal ores
  • metallurgical waste
  • waste dump
Accesso libero

The effect of temperature on the mechanical properties and workability of rock salt

Pubblicato online: 07 Nov 2019
Pagine: 384 - 393

Astratto

Abstract

Underground salt mining accounts for about 16 percent of the total salt production worldwide. When excavating salt rock, the cutters of the road header come into contact with the rock. This produces friction and, consequently, a rise in temperature. Generally, as temperature increases, salt gradually loses its plasticity. The extent of these alterations depends on the presence of other minerals in the rock. This paper presents the results of laboratory tests on regularly shaped samples of salt. An analysis was performed of the results of compressive, tensile and induced-shear strength, and of Young's modulus, Poisson's ratio, cuttability index and side chipping angle. The testing was conducted on samples with a temperature of about 20°C and samples heated to 50°C and 80°C. The tests showed that as temperature increased, so did compressive and tensile strength, and longitudinal and transverse strain of salt. The temperature increase caused, however, a decrease in shear strength. The cuttability index and the side chipping angle also decreased when the heated samples were being cut. The percentage changes in the parameters within the 60-degree temperature range were as high as several dozen percent.

Parole chiave

  • rock salt testing
  • mechanical salt parameters
  • salt cutability
  • temperature change of salt
Accesso libero

Effective utilization of man shift through sustainable workload testing for underground mining machine operators. An ergonomic based man-machine interface approach

Pubblicato online: 07 Nov 2019
Pagine: 394 - 403

Astratto

Abstract

Insight of man-machine interfaces during mining machine operations, better co-ordinance with human efficiencies and suitable workload selection in underground mining machine operation are the main viewpoints of the study. Total 12 side discharge loader (SDL) and load haul dumper (LHD) operators [N = 12] have been taken as participants of the study. The methodology is divided into two parts first part is devoted to measuring and analyzing workload response of machine operation with polar heart rate monitor. Machine operator’s heart rate ratio (HR ratio) for the whole shift is recorded and metabolic rate (MR) has been analyzed. Additionally, fatigue sustainability (FS) and degradation of muscle force (MF) are recorded for each work cycles up to exposure time period (ETP) of 360 minutes. In the second part of the methodology, based on the HR ratio recorded during the mining operation, a workload simulation study is undertaken on a treadmill at the surface following BRUCE protocol. At treadmill, based on HR ratio, workload achieved from mines along with three different workloads i.e. low, moderate and high has been tested. Differences in FS and degradation rate of MF after each workload experiment have been recorded. A result from the underground operational study shows that there is about 43.2% and 32.4% of decreasing MF for SDL and LHD operators after end of spells at mines. Additionally, a negative correlation (r = −0.99) is found between ETP and MF. The workload simulation study shows that there are significant differences between FS (p < 0.05) and MF (p < 0.05) data of mining and treadmill experiment with the same workload. In comparison to an underground operation, FS rate of low, moderate and high workload is recorded 60%, 35%, and 15% higher respectively than of mine workload. Higher FS rate may achieve due to availability of good environment. Among the tested workload only low kind of workload is found suitable for mining machinery job as degradation of MF is found significantly (p < 0.05) low and FS is found significantly (p < 0.01) high in this kind of workload. Therefore, it can be concluded that in mining machinery operation better to adopt low workload for effective utilization of man shift (EUMS) as it gives comparatively low MF degradation and better FS during continuous work.

Parole chiave

  • Fatigue sustainability (FS)
  • Muscle force (MF)
  • Heart rate ratio (HR ratio)
  • Exposure time period (ETP)
  • Effective utilization of man shift (EUMS)
  • Workload simulation
Accesso libero

Multiple-criteria decision-making for the choice of equipment in mining using the AHP method

Pubblicato online: 07 Nov 2019
Pagine: 404 - 415

Astratto

Abstract

Rational solution for mining equipment based on the use of haul trucks, excavators, wheel loaders and crunchers should result from thorough analysis of technical and economic issues – both cost-related and exploitational - which can have a crucial impact on the cost of minerals extraction. Moreover mining equipment should be selected with consideration for all vital parameters in specific exploitational conditions and even the exploiter’s preferences. This selection should consider hitherto disregarded criteria, such as mean availability and structure utilization of machinery systems with the aim to improve the same. Methodology presented in the paper illustrates practical application of MCDM and one particular method of this type – the Analytical Hierarchy Process (AHP) – for resolving the problem in specific exploitational conditions of mineral resource in surface mining AHP method covers a multi-criteria approach based on a compensation strategy to model preferences and assuming variant comparability. Taking into account the preferences of the evaluator, which determine the subjectivity of comparative evaluation, is the core of the multi-criteria approach, which treats such preferences Considering the above issues, the following paper is an attempt to develop new and universal criteria as well as a method of evaluation and selection of means of mining equipment for mineral resource surface mines.

Parole chiave

  • surface mining
  • mining equipment
  • utilisation
  • reliability parameters
  • Multiple-criteria decision-making (MCDM)
  • AHP
Accesso libero

Haul road roughness measurement using georeferenced truck vibration

Pubblicato online: 07 Nov 2019
Pagine: 416 - 423

Astratto

Abstract

Vehicle vibrations caused by poor haul road conditions create multiple negative effects for mines, including slower cycle times, increased maintenance, and operator injury. Vibration levels in vehicles result in part from road roughness. Mine roads are mainly constructed from in-pit materials that are more likely to deteriorate overtime and require frequent maintenance to maintain a smooth surface. The decision for when and where road maintenance is conducted is primarily based on visual inspections. This method can provide subjective, inaccurate, and delayed response to adverse conditions. The recent increase in vehicle telemetry data allows instant access to several types of data; mainly being used for haul fleet dispatching, collision avoidance, and geologic surveying, telemetry data has yet to see widespread use in road maintenance dispatching. This paper examines current road roughness characterization techniques and current telemetry data streams. An initial case study was conducted using vibration and Global Navigation Satellite System (GNSS) telemetry data to determine road roughness. Data from three haul trucks under normal operating conditions were collected over the course of a week. The results of this case study demonstrate localized vibration levels can be used to objectively identify rough roads. This can be further developed to dispatch road maintenance crews leading to overall reduced mining costs and increased operator health. The researches propose continuing to full scale test using data from an entire fleet and longer timeframe.

Parole chiave

  • Haul Road
  • Vibration
  • Operator Health
  • Road Maintenance
  • Big Data
Accesso libero

Experience of safety monitoring equipment application in the production processes of coal mines in Ukraine

Pubblicato online: 07 Nov 2019
Pagine: 424 - 431

Astratto

Abstract

The analysis of the state of security in the coal mines of Ukraine showed an urgent need for equipment to monitor the safety of production processes, identifying its shortcomings. The necessary regulatory requirements of the legislation of Ukraine on this issue have been considered in detail. A solution to the problem of creating modern equipment for monitoring the safety of production processes in coal mines through a new approach and a change in concept has been proposed.

Parole chiave

  • safety
  • coal mines
  • production process
  • control equipment
  • acceptable risk
Accesso libero

Analysis of measures to enhance energy efficiency and sustainable development of the gas transmission system of Ukraine

Pubblicato online: 07 Nov 2019
Pagine: 432 - 440

Astratto

Abstract

The requirements of the fundamental normative documents in Public Joint Stock Company “UKRTRANSGAS”, regulating activities in the sphere of energy efficiency, are considered and analyzed. The procedure for implementation of energy saving measures and controlling over their implementation is presented. The analysis of planned and actual indicators of fuel and energy resources saving has been carried out. The ways to improve energy efficiency with the use of renewable energy sources are given.

Parole chiave

  • energy efficiency
  • gas transmission system
  • fuel and energy resources
  • energy saving
  • sustainable development
Accesso libero

The strength problems in the operation of drum hoist cages

Pubblicato online: 07 Nov 2019
Pagine: 441 - 449

Astratto

Abstract

From information obtained from periodic surveys of cages used in the shaft of one of the Polish mines, it appears that the majority of registered damages of their supporting elements are fatigue cracks. These cracks are formed and develop mainly in main nodes or welds in the areas of their connection with the construction of the cage. In order to eliminate the causes of these damages and to increase the durability of cages, it will probably be necessary to reconstruct those fragments of the cages in which they occur. In order to determine loadings of load-bearing elements and the state of stress that arises in them during the operation of the device, a numerical model of the cage was developed. The results of the calculations made as well as their analysis form the basis for the assessment of the strength and durability of the load-bearing elements of the discussed cage. The key problem determining the durability of the structure – as shown by the analyzes carried out – is the method of constructing the connection of the strings with the appropriate elements of the cage. Changing this state requires significant structural changes of these nodes, which the authors of this study pointed out.

Parole chiave

  • Drum hoist cage
  • strength analysis
  • fatigue damage
Accesso libero

X-Ray CT inspection of subsurface areas of concretes exposed to fast flowing liquids

Pubblicato online: 07 Nov 2019
Pagine: 450 - 459

Astratto

Abstract

Concrete structures affected for a long time by flowing liquids are exposed to gradual erosion in surface layers caused by a combination of several degradation processes: abrasion, cavitation and chemical or bacterial impacts. Due to the complex phenomena and difficult-to-define initial and boundary conditions, the whole process cannot be easily simulated using the conventional computing tools. Laboratory experimental research is thus the most appropriate approach for the investigation of a suitable composition of concrete resistant to the flowing liquids. However, the methods used are often very time consuming and last even several years. High-speed water flows can be elegantly used for the acceleration of the mechanical simulation of a real situation. Several experiments on the effects of the high-speed water flows on concrete surfaces have been carried out. Using the X-Ray CT methods, subsurface structures of concretes exposed to the accelerated mechanical simulation of the erosion wear caused by fast flowing liquids were investigated and presented in the article. It has been shown that the simulation does not cause initiation of new fractures or cracks in the original concrete structure. The pure water flow mainly removes the hardened cement paste and reveals the aggregate grains. The water flow with abrasive particles disintegrates in greater depths and washes out entire aggregate grains, eventually amputates them and finally smoothens entire surface.

Parole chiave

  • erosion
  • concrete
  • fast flowing liquid
  • high-speed water jets
  • X-Ray CT
Accesso libero

Mining the sparking rocks in the context of most frequent cases of methane ignition

Pubblicato online: 07 Nov 2019
Pagine: 460 - 471

Astratto

Abstract

The article presents the principles of safe cutting of rocks prone to generate igniting methane sparks. A list of methane ignitions and explosions from the sparking of rocks caused by cutting with road header was given. Unusual case of methane ignition in conditions of full technical and technological protection of roadway development is discussed. In conclusions, the importance of an individual approach to geological and mining conditions in the case of the need to cut sparking rocks was emphasized.

Parole chiave

  • sparks
  • methane ignition
  • sparking rocks
  • protection
Accesso libero

The application of the integrated production assets management system in the Polish Mining Group Inc.

Pubblicato online: 07 Nov 2019
Pagine: 472 - 479

Astratto

Abstract

The management of the production assets in the Polish Mining Group Inc. is geared towards achieving strategic aims through the unification of the obtained machines/devices, their practical use while maintaining them in the proper technical condition, adhering to proper maintenance-renovation procedures, reserves optimization as well as final recycling with no re-use in the production cycle. The following paper presents the functioning of the IT support in the production assets management, geared towards the integration with other areas of technical and economic activities of the Group. The modular structure of the integrated IT system makes it possible to gradually implement the successive solutions functioning within the Group as well as in the surrounding local areas, ensuring the suitability to the current needs of the organization and the system users.

Parole chiave

  • production management
  • mining machinery
  • IT systems
Accesso libero

Application of fiber optic FBG techniques in analysis of strain in engineering machines

Pubblicato online: 07 Nov 2019
Pagine: 480 - 485

Astratto

Abstract

The paper presents the use of fiber optic FBG strain sensors for analysis of deformations of machines and devices including those used in mining techniques. FBG strain sensors have many advantages over classic strain measurements using electro resistance strain gauges. They are characterized by a significant measurement accuracy of up to 1 mm, a service life of up to 30 years, the possibility of measuring large deformations of up to 8%, significant fatigue life, the possibility of building measurement networks and, something extremely important in mining – intrinsic safety, because the operating medium is white light. The entire measurement system based on the optical interrogator was also discussed. It enables conducting both static and dynamic measurements. The results of the strain research for an engineering machine, in which the loads had exceeded 800 T, were reported.

Parole chiave

  • optical fiber sensors with FBG fiber Bragg grating
  • strains
  • engineering machines
Accesso libero

Modelling and simulation tests of a quadrocopter flying robot

Pubblicato online: 07 Nov 2019
Pagine: 486 - 495

Astratto

Abstract

In recent years, there has been a dynamic increase in the use of multirotor flying robots in various areas of economic and social life. Robots of this kind may be used in environmental research, after equipping them with an appropriate measuring systems. This includes taking measurements of various types of contaminants, such as: particulate matter (PM), various gases, noise and light pollution. To make this possible, it is necessary to conduct advanced model-simulation tests of the flying platform, analyse and determine the appropriate location for the measurement system. Most of the current research on methods and techniques of taking measurements on the flying platform does not take into account these issues. This work consists of two main parts: modeling and simulation tests, and experimental part carried out in laboratory conditions. As part of the work, quadrocopter dynamics equations have been developed and implemented in the Matlab/Simulink environment. The developed discrete mathematical model made it possible to simulate different robot maneuvers: upward, forward, sideways and rotation flight. In order to determine the required characteristics of the multicopter drive sets, a mobile dynamometer station was designed, constructed and programmed. The dynamometer allows, among others, to take measurements of thrust force, torque and rotational speed. The final stage of the work was the development of the numerical model and CFD calculations of the quadrocopter. In this part, distributions of the pressure fields and velocity for the robot's hover state were determined.

Parole chiave

  • quadrocopter
  • mathematical model
  • CFD simulation
Accesso libero

Revitalization and preservation of biodiversity. Focus on water bodies in the Cracow region

Pubblicato online: 07 Nov 2019
Pagine: 496 - 504

Astratto

Abstract

The studies included 2 water bodies in Cracow (Kraków), 6 water bodies in the commune of Zabierzów (Cracow County) and 4 in the commune of Niepołomice (Wieliczka County). The studies were carried out in June 2018 and May 2019. The ways on management of the water bodies were compared. Problems related to revitalization were identified. One of these problems is the preservation of biodiversity. In some cases revitalization reduces biodiversity. This can happen due to the liquidation or limitation of the reed bed zone. Such a situation was observed in the water bodied of Zelków and Karniowice (com. Zabierzów). Both have ornamental functions now. Removal of most of reed does not disturb mallards (Anas platyrhynchos), but makes it impossible to nest for other birds such as moorhen (Galinula chloropus). Moorhens were observed in two former fish ponds in Staniątki (com. Niepołomice) and in the pond of the Kaczeńcowa street. In one of them revitalization caused the diminishing of the water area, but did not change the character of the water body. Bird species were recorded at water bodies.

Parole chiave

  • ponds
  • revitalization
  • birds
  • biodiversity loss
Accesso libero

Modelling of global solar irradiance on sloped surfaces in climatic conditions of Kraków

Pubblicato online: 07 Nov 2019
Pagine: 505 - 514

Astratto

Abstract

The paper presents calculations of global solar irradiance on inclined surfaces of any orientation in the hourly time step. For computational purposes there were used the data from typical meteorological years (TMY) available in a form of text files on the website of the Ministry of Infrastructure and Development. Hourly solar global horizontal irradiance from measurements from the file for Kraków was used as input for five anisotropic models (Hay, Muneer, Reindl, Perez and Perez according to the new PN-EN ISO 52010-1 standard). Direct normal and diffuse horizontal and then global irradiances were calculated. To illustrate the effects of using different models, for the exemplary residential building, monthly solar heat gains and heating demand was determined according to the monthly method of PN-EN ISO 13790. In comparison to the solar data from the TMY, an average decrease in the value of solar gains amounted 37%, what resulted in an increase in the calculated heat demand of the building by 10%. This is very important since this change takes place without any modernisation works.

Parole chiave

  • Diffuse irradiance
  • anisotropic model
  • sloped surface
  • typical meteorological year
  • EN-ISO 52010-1
Accesso libero

Application of neural networks to the prediction of gas pollution of air

Pubblicato online: 07 Nov 2019
Pagine: 515 - 523

Astratto

Abstract

The issue of projecting the air pollution levels is quite essential from the viewpoint of the necessity to adopt specific prevention measures intended to reduce the pollution concentration in the air. One can apply certain machine learning methods, including neural networks, to build pollution concentration models. Neural networks are characterised by the fact that they can be used to solve the relevant problem when we face shortage of data, or we do not know the analytical relationship between input and output data. Consequently, neural networks can be applied in a number of problems. This paper discusses a possibility to apply neural networks to the prediction of selected gas concentrations in the air, based on the data originating from the measurement networks of the Polish State Environmental Monitoring System, combined with local meteorological data. Forecast results have been presented here for SO2, NO, NO2, and O3 in various locations. The author also discusses the accuracy of the respective forecasts and indicates the relevant contributing factors.

Parole chiave

  • air quality monitoring
  • air pollution
  • artificial neural networks
  • prediction
Accesso libero

Numerical investigation of the drag force reduction for homogeneous column of vehicles

Pubblicato online: 07 Nov 2019
Pagine: 524 - 531

Astratto

Abstract

This paper presents simulation studies on the aerodynamics of vehicles moving in an organized column. The object of research is a column that consist of three vehicles of the same type (homogeneous column). In this research geometry of Ford Transit was used. As a part of the studies, the air drag forces acting on individual vehicles were calculated. The results are presented in dimensionless drag coefficient. The influence of the distance between cars on the generated force was also determined. In the first stage of the work, a numerical model was developed based on the Ahmed body reference structure. The calculations were carried out for 9 different velocities. The obtained results of the drag coefficient were compared with the work of other authors. The applied turbulence model and parameters of the boundary layer were used to create a numerical model of a moving column of vehicles. Mesh independence for numerical model of van was verified. The Finite Volume Method was implemented in the ANSYS Fluent program and used for the calculations. The use of supercomputers was necessary due to the large size of the grid.

Parole chiave

  • aerodynamics
  • platooning
  • RANS
  • CFD
  • vehicles
Accesso libero

Opportunities of re-establishing underground mining in the borsod coal basin in north-eastern Hungary

Pubblicato online: 07 Nov 2019
Pagine: 532 - 540

Astratto

Abstract

Numerous underground coal mines were in operation in the Borsod coal basin in northeastern part of Hungary until the beginning of this century. The main area of utilization of the mined out coal beside power and heat generation was supplying households with fuel mostly for heating. In the beginning of the 1990ies the power plants in question were shut down for economic, environmental and technical reasons. Consequently all the mines were closed no later than 2004 and thousands of miners lost their jobs. A new perspective of coal mining can be enabled by other ways of utilization of coal, e.g. coal chemistry, etc. Safe and modern equipment and technology enabling high output, clean coal, furthermore high rate of yield are targeted. Opportunity of sustainable underground coal mining in the north-eastern part of Hungary is discussed in the paper. Analysis of the properties of coal deposits using three-dimensional (3D) modelling are used for considering opportunities of new mining operations. Models are being developed.

Parole chiave

  • underground mining
  • sustainability
  • clean coal
  • coal
Accesso libero

Green energy from a hybrid PV panels and wind turbine farm in Lebanon

Pubblicato online: 07 Nov 2019
Pagine: 541 - 548

Astratto

Abstract

The publication presents the results of analysis of green energy from a hybrid PV panels and wind turbine farm use in Lebanon. Electricity is one of the most critical problems in Lebanon. This publication presents an effective solution to this issue. It deals with the generation of green environment friendly electricity from photovoltaic (PV) panels and wind turbine. The genuine idea consists of placing these panels and turbines at the middle of the coastal highway since it is considered as a free land. The produced energy is fed directly to the off gird after being inverted using appropriate devices. The middle of the highway from Tyre to Sidon is considered to apply this research. The actual design consists of 15222 PV panels placed in pairs on a steel chassis among the entire 27300 m coastal distance, 2 meters wide and 7610 vertical axis wind turbines placed at a distance of 0.9 m away from each pair of PV panels. The total energy produced by the PV system is estimated to 7.4 GWh/y and 3.1 GWh/y at an average wind velocity of 4.04 m/s. In addition to its benefit from a free land, the produced energy is environment friendly since there is no carbon dioxide emission.

Parole chiave

  • Vertical Axis Wind Turbine
  • PV Panel
  • Carbon Dioxide
Accesso libero

Local benefits factored in utility scale wind energy for a remote location

Pubblicato online: 07 Nov 2019
Pagine: 549 - 554

Astratto

Abstract

The publication presents the results of analysis of possible local benefits factored in utility scale wind energy for a remote location. Electricity is one of the most vital problems on the Earth, thus utility scale wind and solar energy devices are boosting economic development. Energy demand is constantly increasing, despite efforts to ensure the energy efficiency of devices. People are looking for more energy and electricity to consume. Although wind energy is still being researched and improved, modern generation of wind energy is becoming more and more effective and desirable. This publication presents an effective solution to this issue. It deals with the generation of green environment friendly electricity from wind turbine. The genuine idea is to provide energy for remote location using onshore wind turbines. An analysis of the demand for energy at a remote location and electricity consumption was made to provide preliminary calculations of the wind farm. The number of required turbines is determined taking into account all related factors. A specific wind turbine has been selected and proposed to provide the necessary location with the necessary amount of energy. The analysis carried out showed that the produced energy is environment friendly since there is no carbon dioxide emission.

Parole chiave

  • Horizontal Axis Wind Turbine
  • Energy Generation
  • Greenhouse Gases
Accesso libero

Areas of industrial damages in upper Silesian industrial region versus recultivation or revitalization ?

Pubblicato online: 07 Nov 2019
Pagine: 555 - 561

Astratto

Abstract

Areas of industrial damages require elaborating efficient methods of reclamation and revitalization. A region of Poland, where process of degradation is particularly visible is Upper Silesian Industrial Region. Areas in the zone of many-years influence of Huta “Miasteczko Śląskie” are characterized by norm-exceeding concentration of heavy metals. The area in its direct surrounding was defined as industriogeneous desert. In 2017 on three designated testing grounds with diversified degree of contamination (see: map) of joint area of 1.5 ha, planted were jointly 6550 seedlings of chosen species of trees and bushes which were likely to survive in those conditions. In the first vegetative season, despite extremely long-lasting drought and high temperatures, the seedlings showed high survivability. It amounted 82% on industriogeneous desert (testing ground C) and 90-95% on forest testing grounds (A and B). Maples stood out among other trees with proper development and condition. The highest seedlings, especially mountain ash, birch and European red elder already in August had burnt top shoots and numerous necroses on leaves. Introduction of plants – hyperaccumulators of heavy metals, especially on industriogeneous desert will influence positively on condition and development of seedlings in future vegetative seasons.

Parole chiave

  • industriogeneous desert
  • reclamation of industrial areas
  • species tolerating contamination by heavy metals
Accesso libero

The use of mathematical modeling for the construction of a control system for a climate chamber

Pubblicato online: 07 Nov 2019
Pagine: 562 - 569

Astratto

Abstract

Due to the introduced political instruments, as well as the increase in awareness and standard of living, mechanical ventilation is becoming more and more popular in Poland. The growing market and standards force the manufacturers of air handling units to constantly improve the quality of their products. In order to verify the operation of these devices, it is necessary in a specially adapted for this object called the climate chamber. Due to the strict regulations regarding the working conditions of the said facilities, it is necessary to apply the processes of advanced control systems in the process of regulation. These processes are aimed at establishing stable parameters of air supplied to the tested objects, ventilation and air-conditioning units such as: temperature, humidity, flux. Due to the need for precise control and operation of the installation in industrial conditions, it was decided to use the PID controller. The article deals with the optimization of the heating and cooling system, because the temperature parameter was a problematic element in the proper operation of the climate chamber. Both the heating and cooling systems have been described and executive elements have been emphasized, thanks to which it was possible to control the flow of circulating factors. The procedure of selection and implementation of the regulator's settings and its influence on the operation of the climate chamber was also analyzed.

Parole chiave

  • ventilation
  • recuperation
  • climatic chamber
  • PID controller
  • optimization
Accesso libero

Wound image segmentation using clustering based algorithms

Pubblicato online: 07 Nov 2019
Pagine: 570 - 578

Astratto

Abstract

Classic methods of measurement and analysis of the wounds on the images are very time consuming and inaccurate. Automation of this process will improve measurement accuracy and speed up the process. Research is aimed to create an algorithm based on machine learning for automated segmentation based on clustering algorithms Methods. Algorithms used: SLIC (Simple Linear Iterative Clustering), Deep Embedded Clustering (that is based on artificial neural networks and k-means). Because of insufficient amount of labeled data, classification with artificial neural networks can't reach good results. Clustering, on the other hand is an unsupervised learning technique and doesn't need human interaction. Combination of traditional clustering methods for image segmentation with artificial neural networks leads to combination of advantages of both of them. Preliminary step to adapt Deep Embedded Clustering to work with bio-medical images is introduced and is based on SLIC algorithm for image segmentation. Segmentation with this method, after model training, leads to better results than with traditional SLIC.

Parole chiave

  • clustering
  • segmentation
  • machine learning
  • neural networks
  • wounds
Accesso libero

Intelligent system for monitoring the air pollution of the city in real time

Pubblicato online: 07 Nov 2019
Pagine: 579 - 588

Astratto

Abstract

The article reveals the theoretical foundations, types of pollutants, classification of monitoring and visualization systems of air pollution. A description of the design of the structure of the system is described, its components are described in detail, and the justification of the selected technologies is given. In general, the system consists of two parts: a device for collecting air pollution data and a site that displays these data in user-friendly form. Graphic images that display the appearance of a software product are also added.

Parole chiave

  • API – application programming interface
  • CAQI – Common Air Quality Index
  • EEA – European Environment Agency
Accesso libero

Numerical modeling of vertical axis wind turbine with air guides

Pubblicato online: 07 Nov 2019
Pagine: 589 - 595

Astratto

Abstract

Currently, obtaining energy from renewable sources, as never before, it has become one of the most important areas, but at the same time challenges in human activities. This is the effect of many factors simultaneously, including because of the media trumpeted the greenhouse effect, the necessity of reducing CO2 emissions, shrinking natural resources, and thus the desire to protect their welfare including conservation (including natural resources) for future generations. The paper presents the results of preliminary numerical analyzes of work for vertical axis wind turbines equipped with air guides. The carried out analyzes indicate the potential possibility of using this type of construction in practice. The obtained power factor value is higher than in classic wind turbines with a vertical axis. The conducted analyzes also indicate the possibility of optimizing the proposed constructional solution in order to increase efficiency of obtaining energy from the wind.

Parole chiave

  • Vertical axis wind turbine
  • numerical modeling
Accesso libero

Performance evaluation of continuous miner based underground mine operation system: An OEE based approach

Pubblicato online: 07 Nov 2019
Pagine: 596 - 603

Astratto

Abstract

CM is a globally renowned machine, designed to work as a mass production technology for underground coal. Different major coal producers across the globe are using this technology for decades to produce underground coal efficiently. India is also one of the major players globally in the arena of coal production and adopted this cutting edge technology since last decade by implementing at. few of the selective underground coal mining projects. Performance of CM technology is influenced by the geo-mining condition, fleets of other ancillary units and reliability of subsystems while implementation of this system depends largely on the extent of reserve. These aspects generate a scope of large scale research and development in this field. Overall Equipment Effectiveness (OEE) is the parameter to benchmark the equipment performance globally. OEE is the product of equipment availability, performance and product quality. This mining machine based paper focuses on the Overall Equipment Effectiveness (OEE) of the complete CM based operation to identify the vulnerable systems, which helps to design proper preventive maintenance programme. The CM based system is divided into few subsystems, such as; electrical, cutter, gathering arrangement, traction, hydraulic, chassis, feeder breaker, shuttle car, CM conveyor and out-bye conveyor. The downtime data used for this analysis is collected from an underground coal mine situated in the central part of India, belongs to one leading coal producing company of the country. From analysis it was found that, electrical systems and conveyors are among most vulnerable systems and deserves more care during maintenance. On the basis of these results recommendations are made to redesign the Preventive Maintenance Programme, in order to avoid the lower availability as well as lower OEE.

Parole chiave

  • Continuous Miner
  • Overall Equipment Effectiveness
  • Availability
  • Performance
  • Quality
  • Reliability
Accesso libero

Suppliers and their role in modern enterprise – Case study

Pubblicato online: 07 Nov 2019
Pagine: 604 - 612

Astratto

Abstract

For each company, the process of selecting and evaluating suppliers of both the components needed for production and the implementation of production process is a very important aspect of their business, as the selection of appropriate contractors has an impact on the quality of final product, which is offered to customers. Dynamically changing situation in the company’s environment causes that success is achieved by those companies which implement new solutions and tools in their relations with suppliers. One such solution may include the PN-EN ISO 9001:2015 standard, which requires the organization to evaluate and select suppliers, taking into account their ability to provide a product compliant with the organization’s requirements. This paper presents a proposal to supplement the procedure of supplier qualification in a selected company. Attention was drawn to the fact that it is necessary for the modern organization to have access to database of qualified suppliers, who at the time of arising demand are able to meet the requirements set for them. It is also important for the enterprise to have at least two qualified suppliers for the same component in its database. Such an approach results from the current market requirements. The paper is based on a case study as a recognized method of analyzing and discussing authentic situations applied in management sciences.

Parole chiave

  • quality
  • suppliers
  • supplier evaluation
  • ISO 9001 standard
66 Articoli

Part 1: Modern Machines and Technologies for Mining, Editor: Krzysztof Kotwica

Accesso libero

Assessment of efficiency in reduction of dust concentration in mineral processing plants using the state-of-the-art technical measures

Pubblicato online: 07 Nov 2019
Pagine: 11 - 19

Astratto

Abstract

Airborne coal dust hazard at the workplaces in hard coal processing plants in Poland is presented. The methods for dust control in coal processing plants are discussed. The results from testing the dust control efficiency at the workplaces are given. The test results of airborne dust concentration are analysed as well as advantages and disadvantages of used technical measures are indicated.

Parole chiave

  • mechanical coal processing plant
  • coal dust
  • airborne dust control
  • dust removal
  • spraying
Accesso libero

Components of an innovative electro-control system for undeground mining – analysis

Pubblicato online: 07 Nov 2019
Pagine: 20 - 27

Astratto

Abstract

In the era of Industry 4.0, coal companies began to reach for new innovative technologies that increase work safety and their possible use affects the economic improvement of companies. One of them is to equip a powered roof support section with an electrohydraulic control system with a monitoring system that tracks operating parameters. The development of a monitoring system for a powered roof support is a key investment in new longwall complexes. It allows rapid diagnostics of status of the support. Currently used system designed to control the powered roof support are based on blocks of manually controlled distributors. The pilot control is currently the leading control that properly functions in all conditions, allowing to adapt to the requirements resulting from the construction of the section. A number of tests and analyses must be conducted prior to introducing the new control based on an innovative approach into operation. The basic research has focused on identifying the user interface that will potentially be the solution for the entire system. The user has defined how the driver should look like and how it will be operated and maintained. The results of the first series of tests on the elements of an innovative electronic control system of the powered roof support enabled to develop a prototype version. The assumptions for the system were verified during the conducted development studies. The article presents preliminary results of development research for devices included in the innovative control system of the powered roof support.

Parole chiave

  • fire hazards
  • powered roof support
  • natural hazard
  • nitrogen cushion
Accesso libero

Examples of vibratory crushers applications in crushing technological lines

Pubblicato online: 07 Nov 2019
Pagine: 28 - 36

Astratto

Abstract

Very fine crushing of hard and very hard materials, to product of particle size less than 2-4 mm at feed particle size of 50-200 mm, requires a very large energy inputs. This is mainly because of the need for at least three or even four degrees of crushing, containing: jaw, cone or impact crushers. One of the methods of reducing the amount of energy expended on the crushing process is reducing the number of crushers in technological line. By replacing a large number of less effective crushers with fewer machines but characterized by higher crushing efficiency we can gain considerable savings in investment and operating costs. This is possible by using crushers capable of obtaining much greater degrees of fragmentation than the aforementioned, that is vibratory crushers. The paper includes the systematic of currently used vibratory crushers, their mechanical diagrams, descriptions of the construction and operation, and basic technical parameters as well as examples of crushing technological lines utilizing vibratory crushers.

Parole chiave

  • crushing
  • vibratory crushing
  • vibratory crushers
Accesso libero

Determination of boom vibrations of the road header during cutting based on the analysis of images from high-speed cameras

Pubblicato online: 07 Nov 2019
Pagine: 37 - 49

Astratto

Abstract

Excavation, especially of hard rocks, using boom-type road headers is a source of strong vibrations of the boom in which they are equipped. These vibrations are transferred through construction nodes further to the turntable and the body of the road header. On the one hand, they are of great importance from the point of view of the durability and the reliability of the mining machine. On the other hand, they affect the variability of the parameters at which the process of cutting the heading face surface of a drilled roadway or tunnel is carried out. For the purpose of determining the vibration intensity of the boom of the road header a photogrammetry system based on two high-speed cameras Phantom Miro LC 120 was used. During the experimental investigations of the cutting process of a cement-sand block using the R-130 road header, the boom and turntable movements were recorded. The analysis of the time-lapse pictures of the recorded footage obtained from the high-speed cameras using dedicated TEMA 3D software allowed to determine the spatial trajectory of movement of the boom and the turntable during the cutting of the massive with specified mechanical properties with set values of the parameters of this process. Basing on the time courses of the coordinates of the boom and turntable characteristic points, the courses of the actual boom swinging speed and acceleration components of its vibrations were determined. The intensity of these vibrations was related to the conditions of the cutting process.

Parole chiave

  • road header
  • cutting process
  • vibrations
  • measurement
  • high-speed cameras
Accesso libero

Drilling and bolting rigs operator support using FGS (Feeder Guiding System) and remote control

Pubblicato online: 07 Nov 2019
Pagine: 50 - 58

Astratto

Abstract

The article presents the assumptions and main functionalities of two operator support systems – the FGS (Feeder Guiding System) and the remote control system of a drilling or bolting rig. Both of these systems greatly facilitate the work of an operator of a self-propelled mining vehicle in the conditions of an underground metal ore mine. The first of the described system allows for real-time control of the current position of the mining boom and facilitates the drilling of blast holes according to a predetermined drilling pattern. The second of the systems – a remote control system – is used especially in conditions of unstable rock mass or in the case of work in particularly difficult operating conditions, where it is advisable to limit the presence of the crew from the face-up to the necessary minimum. The intensity of these vibrations was related to the conditions of the cutting process.

Parole chiave

  • drilling rig
  • bolting rig
  • drilling control
  • remote control
  • drilling feeder system
Accesso libero

Methods of enlarging material to the concentration table

Pubblicato online: 07 Nov 2019
Pagine: 59 - 68

Astratto

Abstract

Concentration tables are one of the oldest oscillatory enrichments with over 100 years of tradition. On this type of distribution tables are made according to material mass in many recurring cycles induced by appropriate drives. So-called wet tables are the devices most often used for coal enrichment in Polish mines because this process generates very high costs, high water consumption and pollution of the environment, as well as the need for, among others, water and mud management is increasingly being replaced mainly in areas poor in water by the modern model of the air concentration table – FGX produced in China. The process of enrichment on this type of table itself runs in a manner comparable to the method of wet enrichment with the difference that the FGX is distributed on a perforated plate, in this case we deal with air pollution. Department of Machinery Engineering and Transport's attempts to use the differences in coefficients of friction in over-resonance screens have shown that it is possible effective separation of grains with different coefficients of friction. The article presents a theoretical analysis and presents the results of performed dry enrichment trials using different coefficients of friction. The summary presents the advantages of using the enrichment method using the differences in friction coefficients and test results.

Parole chiave

  • concentration table
  • coefficient of friction
  • enrichment
Accesso libero

Modified ground support with alternative fill material for ground control at munsar underground manganese mine of moil limited, India

Pubblicato online: 07 Nov 2019
Pagine: 69 - 77

Astratto

Abstract

MOIL Limited is operating 7 underground and 3 opencast mines in central India and producing annually more than 1.3 million tonnes of various grades of manganese ore. The underground mines are operating at shallow – 90 m at Munsar mine to moderate – 353 m at Balaghat mine below the surface with horizontal cut and fill (HCF) or its variant method of stoping with post filling by hydraulic sand stowing. The Munsar mine is being worked underground since 1903. The opencast mining is presently stopped. The ore body below the opencast quarry is geological continuity of the area excavated in past by opencast method of mining. The underground mining is done through the adit in three levels i.e. 270’L, 220’L, 170’L and by incline in western part of the property at 70’L. The horizontal drift development has been developed in the manganese ore body with sill drive of 5 m above the sill pillar in lower level at 70’L and barrier pillar of 5 m thickness is left for protection of upper level at 170’L. Valuable mineral has been locked in sill pillar and therefore rock mechanics investigations have been carried out. On the basis of study now the drift development has been carried out in footwall rock at 70’L, (-) 30’L and below levels and it has improved the minable manganese ore by about 20%. In this modified HCF stope design, an alternative fill material in place of sand, which has been developed in house by use of overburden (OB) material after treatment, has been used for hydraulic stowing. The experimental trials find out that the alternative fill material of OB is more compact and forms a non-expansion floor for the men and machines in the stope. This will certainly help in the introduction of mobile underground mining equipment for drilling in the stopes and mechanical mucking, transportation and loading of the ROM. The paper presents rock mechanics investigations and future use of alternative fill material of overburden material after heat treatment for better safety and productivity at Munsar Mine of MOIL.

Parole chiave

  • Cable Bolting
  • Heat Treatment
  • Overburden
  • RMR
  • Stowing
Accesso libero

Next generation technology for utilization of alumina rich iron ore tailings in India

Pubblicato online: 07 Nov 2019
Pagine: 78 - 85

Astratto

Abstract

Accumulation of low-grade iron ore tailings (IOTs) generated during the processing of high-grade iron ore has become a great threat to environment. Although wide range of research works has carried out to recover the iron values from the IOTs, but the solid recovery value has limited to ca. 50% in Indian context. In order to attain a maximum iron recovery and to utilize these solid wastes for future needs, an attention has shed on the topics of hydrometallurgy and applied nanomaterial synthesis from IOTs. Iron containing nanoparticles (ICNs) have huge potential in environmental and energy related applications. A wide range of synthesis methods has developed to produce ICNs from the mine waste. It is evident from the recent research works that converting waste materials into value added products are gaining more attentions. Objective of this review is to analyse the green synthesis routes to prepare ICNs from mine waste, starting from the physio chemical identification of waste material followed by discussion on various methods of ICNs synthesis routes from mine waste. It includes selective leaching method. Finally, the use of ICNs for environmental application had discussed in brief

Parole chiave

  • Iron ore tailings (IOTs)
  • Hydrometallurgy
  • Mineral processing
  • Iron containing nanoparticles (ICNs)
Accesso libero

Modern grinding balls sorting machines

Pubblicato online: 07 Nov 2019
Pagine: 86 - 95

Astratto

Abstract

Raw materials produced in large quantities are ground in ball, vibratory and stirred ball mills. In mills, the working parts are grinding balls. During grinding, grinding balls wear, change their diameter and lose their shape. The effect of this is the unfavourable change in the grinding balls parameters, which results in deterioration of the technological conditions of the milling process. Relevant parameters of the grinding balls set are restored during maintenance shutdowns. Grinding balls are sorted into appropriate size classes; grinding balls that are not suitable for further use are rejected, and then a set of grinding balls with appropriate parameters is used again. The time needed to prepare the required set depends mainly on the sorting time. To reduce this time, appropriate grinding balls sorting machines are used. The paper presents major problems associated with the grinding balls sorting process, a comparison of modern types of grinding balls sorting machines, a description of their construction and technological parameters.

Parole chiave

  • grinding media
  • grinding balls
  • sorting machine
  • sorting TAB
  • balls sorter
Accesso libero

Drive simulation tests for electric drilling rig

Pubblicato online: 07 Nov 2019
Pagine: 96 - 103

Astratto

Abstract

The article presents methodology and selected results of simulation tests of diesel and electric dive system for drilling rig. Research in this field were conducted under the project no. POIR.01.01.01-00-D011/16 entitled „New generation of modular rigs, drilling and bolting, with battery drives, designated to work in underground cooper ore and raw rock material mines”. The project is funded by the National Center of Research and Development (NCBiR). The aim of the project is to design and implementation of innovation drilling and bolting rig with electric drive system. Due to the complexity of the structure of the drive system (mechanical, hydraulic and electrical elements), it was necessary to use advanced simulation software dedicated to multiphysics analysis. Data presented in the article can be used as guidelines in design process of drilling and bolting rigs as well as in optimization their driving system and mechanical construction.

Parole chiave

  • drilling rig
  • bolting rig
  • electric drive system
  • dynamic simulation
Accesso libero

Innovative system for monitoring the tip over stability of mobile excavating machines on a tracked undercarriage

Pubblicato online: 07 Nov 2019
Pagine: 104 - 111

Astratto

Abstract

The article points out that the operational safety of mobile excavating machines can be significantly improved by equipping them with on-board systems for tip over stability monitoring. Critical analysis has been conducted on tip over stability monitoring systems available on the market. Their capabilities and limitations have been analysed. The second part of the article presents an innovative concept of on-board systems for monitoring tip over stability in tracked excavating machines. This concept was developed to create a device that would allow the vehicle's tip over stability to be monitored with greater accuracy and reliability compared to current systems of this type. The article also presents a demonstrator and a simulation model of the developed device. The final part of the article presents exemplary results obtained in preliminary simulation tests of the developed system.

Parole chiave

  • tip over stability
  • operator assisting system
  • monitoring system
  • mobile excavating machines
Accesso libero

Functional structure of battery drive for self-propelled mining rig used in room-pillar ore exploitation system

Pubblicato online: 07 Nov 2019
Pagine: 112 - 120

Astratto

Abstract

The article presents the structure of the battery drive of a self-propelled mining vehicle on the example of a drilling rig, used in the room-pillar system of copper ore exploitation. Such solutions, due to the ore mining in increasingly difficult operating conditions, are becoming more and more popular in the world. The main assumptions required for the synthesis of this type of drive were indicated, as well as the adopted structure of such a solution was described. The selection of the appropriate drive structure determines the final work characteristics of the self-propelled mining vehicle, and thus the actual suitability of such a machine for use in mining conditions. The paper also details the main technological advantages of this type of drive over classic internal combustion drives.

Parole chiave

  • drilling rig
  • bolting rig
  • battery drive
  • hard rock mining
  • electromobility
Accesso libero

Designing process of a toothed segment of the KOMTRACK haulage system

Pubblicato online: 07 Nov 2019
Pagine: 121 - 129

Astratto

Abstract

The following stages of a designing process of the toothed haulage segment are presented in the article. The toothed segment, developed within the framework of the KOMTRACK project, is an element of an innovative haulage system for highly productive longwall complexes. The project, according to the Contract No. POIR.04.01.04-00-0068/17, realized by the consortium: KOMAG, AGH University of Science and Technology, Foundry Institute, Specodlew Innovative Enterprise of Foundry Engineering, Ltd. and Polish Mining Group, J.S.C., is co-financed with the means of the European Regional Development Fund. The toothed bar, made of toothed segments of the haulage system, works together with the track wheel of a shearer haulage unit. A distinguishing feature of the newly designed haulage system, in relation to the system used at present, is its flexibility enabling individual toothed segments to adapt to longitudinal and transverse curvatures of the longwall conveyor track, which guarantees a correct cooperation with the track wheel.

Parole chiave

  • longwall system
  • shearer
  • shearer haulage system
  • toothed segment
  • gear wheel
Accesso libero

Ageing Process of Hydraulic Oil in Single-Bucket Excavators in Rock Mining

Pubblicato online: 07 Nov 2019
Pagine: 130 - 139

Astratto

Abstract

The paper presents the problem of ageing processes of hydraulic oils when used in single-bucket excavators in mining of rock raw materials. Working parameters of these excavators are specific, particularly when a hydraulic hammer is mounted in place of the working bucket, therefore the course of the oil degradation process and the change times should be precisely determined as full functionality of hydraulic systems of excavators must be maintained and the wear of individual components of these systems should be reduced. Research on oil ageing processes has been carried out for excavators from various manufacturers that have operated in mines of rock raw materials of various raw material extraction quantities. The methodology adopted for testing the ageing processes of oils in excavators allowed to obtain a number of results that question the hitherto applied criteria for quality assessment of used oils in relation to the time of their actual use in hydraulic systems of excavators, as well as the time of change of such oils.

Parole chiave

  • single-bucket excavators
  • hydraulic oil
  • oil ageing process
  • quality testing of hydraulic oil
Accesso libero

Experimental identification of the impact of sectional satellite wheels on the load distribution in the meshing of the planetary gear in mining machines

Pubblicato online: 07 Nov 2019
Pagine: 143 - 152

Astratto

Abstract

This article attempts to solve the problem of load compensation in mesh planetary gearing, with the innovative design idea, resulting from the increased plasticity of the planet wheels (satellite). The cognitive main objective of the experimental work was carried out to identify the comparative effect of the split narrow planet gears, on the load distribution on the length of the teeth of the planet gears of the central wheel of the planetary gear. Achieving this aim, in addition to in-depth analysis, requires experimental research on a specially-built test stand and simulation tests on a solid model of the transmission using the finite element method (FEA). This article presents the concept of a novel test stand, design methodology and research on the influence of the sectional satellite wheels on the load mesh of planetary gears in mining machines.

Parole chiave

  • drive system
  • planetary gear
  • load condition
  • design methodology
Accesso libero

Simulation of the frequency response of the ERC 1400 Bucket Wheel Excavator boom, during the excavation process

Pubblicato online: 07 Nov 2019
Pagine: 153 - 167

Astratto

Abstract

The paper deals with the modal analysis and frequency response analysis of a bucket wheel excavator (BWE) boom, obtained by simulation, based on a virtual model of an existing BWE boom. The boom, which generally is realized as a spatial truss, is the most vulnerable subsystem of the BWE, being submitted to severe operational loads characterized by very pronounced cyclical, dynamic and stochastic variability. This vulnerability is the consequence of its shape and constructive parameters and the nature, source and character of the external exciting loads to which it is exposed. The classical approach recommended by standards and norms cannot predict the occurrence of failures caused by vibration, which produces fatigue due to the load’s cyclical variability and the deformation produced by resonant vibration of some constitutive elements. As exciting load we considered the operational forces acting on the bucket wheel. In this manner we can take into account the constructive features – with modal analysis, and the vibration regime – with frequency response analysis. The proposed method is useful both in the design phase of new load-bearing structures of truss type subjected to high-variability forces, and also in refurbishment or improvement phases of the existing structures of this kind.

Parole chiave

  • Bucket wheel excavator
  • damping
  • frequency response
  • modal analysis
  • resonance
Accesso libero

The use of flat steel-polymer supporting ropes in mining multi-pole hoisting devices

Pubblicato online: 07 Nov 2019
Pagine: 168 - 177

Astratto

Abstract

The paper presents the development of a series of flat steel and polymer bearing ropes using a polyurethane polymeric material (the name of NPSP – flat steel-polyurethane). These ropes are intended for mining extraction devices with friction drive (multi-mill drive wheel, multi-rope drums with a number of ropes from 3 to 12 pieces). The authors of this article have presented a comparison of the drive power of a selected multi-mine mine hoist device with a classic steel round rope with the same extractor in which steel and polymer flat carrying ropes were used. The article also presents the development of mining construction of hoisting equipment, which includes the use of new rope ropes. Very positive results from exploitation in Polish mining of flat steel-rubber balance ropes (durability up to 12 years) can be the basis for the use of such ropes as supporting ropes. Flat steel-polymer supporting ropes, in which the matrix can be rubber or polyurethane or other plastic material, could contribute to increasing the durability of load-bearing ropes due to anti-corrosion protection as well as to reduce the dimensions of drive wheels and rope hoisting machines, and thus to lower the power of the winding machine (as a result of reducing the moments of inertia of the propeller, propulsion and rope). It is also worth mentioning that the NPSP carrying ropes can work directly on steel coatings of propeller drums with proper positioning, created by clamping elements (wood, plastic or aluminum blocks).

Parole chiave

  • ropes
  • flat
  • polymer
  • polyurethane
Accesso libero

Fem stress analysis of a barrel reamer

Pubblicato online: 07 Nov 2019
Pagine: 178 - 185

Astratto

Abstract

Horizontal Directional Drilling (HDD) is a method of installing underground pipelines, cables and service conduit through trenchless methods. The tools and techniques used in the HDD process are an outgrowth of the oil well drilling industry, too. Installation of a pipeline by HDD is a three stages process. The first stage consists of directionally drilling a small diameter pilot hole along a designed directional path. Drilling fluid is pumped through the drill pipe to the drill bit where high pressure jets and the bit will grind the soils ahead of the drill stem. The second stage involves enlarging this pilot hole to a diameter suitable for installation of the pipeline. A reamer is pulled back and rotated while pumping drilling fluid to cut and remove solids to enlarge the hole. A kind of reamer is the subject of this paper. The final stage consists of pulling the pipeline back into the pre-reamed hole. The most important part of the mechanical analysis is to define the boundary conditions for operating situations when the tool is under maximum load. In this paper we present a helpful description for giving boundary conditions to perform the numerical simulation of a barrel reamer.

Parole chiave

  • HDD technology
  • reamer
  • FEM
  • stress
  • displacement
Accesso libero

The new method for assessing rock abrasivity in terms of wear of conical picks

Pubblicato online: 07 Nov 2019
Pagine: 186 - 194

Astratto

Abstract

During the exploitation of mineral raw materials, a cutting tool is an element that is directly in contact with the unmined stone being cut. The most commonly used cutting tools include conical picks. The increasing pressure to reduce mining costs causes an increasing demand for affordable and reliable ways to increase the reliability of mining machines. Abrasive wear is the most common process affecting the wear of shearer picks, hence a good and simple laboratory method for assessing rocks abrasivity is needed. The new method was developed in the aspect of selection of conical picks with appropriate protection of the pick working part, increasing its durability. The method involves the assessment of mass abrasive wear of a standard steel pin and rock sample, and the determination of the abrasivity index Wz of the tested rock, as the ratio of the mass loss of the steel pin to the mass loss of the rock sample. The article presents the procedure of conducting tests, construction of a laboratory test stand and the use of the developed method to assess the abrasivity of gangue rocks occurring in the currently cut tunnel excavations of Polish hard coal mines.

Parole chiave

  • test method
  • assessment of abrasivity
  • conical picks
  • abrasive wear
  • underground mining
Accesso libero

An attempt to increase technological capabilities of laboratory vibratory mills by changing the construction of chamber

Pubblicato online: 07 Nov 2019
Pagine: 195 - 205

Astratto

Abstract

The paper presents the issues related to the grinding process in the vibration mills with low vibration frequency. These mills are rated among devices with high energy of impacts with much wider potential of industrial use than the classic gravitation mills. In vibratory mills there is an unfavorable decrease in the intensity of the grinding process along with the increase in the chamber diameter, which makes it impossible to achieve high performance of such devices. One of the ways to reduce or eliminate this occurrence is to intensify the load movement inside the chamber – this is the subject of this article. The article shows that in a vibrating mill of periodic action it is possible to increase its technological capabilities by application of an appropriate cylindrical component permanently installed inside the milling chamber. The paper also presents an attempt to increase the technological capabilities of a laboratory continuous vibratory mill.

Parole chiave

  • mills
  • vibratory mills
  • fine grinding
  • high energy mills
Accesso libero

Study of the efficiency of the large-diameter fishing tools with the moving magnetic systems

Pubblicato online: 07 Nov 2019
Pagine: 206 - 213

Astratto

Abstract

The variety of accidents which happen during the construction of oil and gas wells causes the expansion in the use of magnetic fishing tools. However, the known tools based on permanent magnets have a significant drawback involving the flat working surface of the magnetic system that does not permit to achieve a considerable attraction force to a fished object of complex geometric shape. Therefore, the aim of the research is to increase the efficiency of removalthe objects of irregular geometric shape from the wells by enlarging the area of contacting them. For that purpose, it has been developed a fundamentally new design of the large-diameter fishing tool with the moving magnetic systems capable of copying the shape of the objects to be fished. Each magnetic system, which is compound of permanent rare-earth neodymium magnets and concentrically placed magnetic cores, shall be held by the magnetic field of adjacent systems with opposite polarity. There were conducted theoretical studies using the finite element method to determine the working capacity of the designed tool. As a result, it has been found the valueof hoisting capacity during the interaction of magnetic systems with the roller cone of the drill bit; this fact confirms the capability of fishing the objects of irregular geometric shape. In addition, it has been explored the influence of the material of the fished object on the power characteristics of magnetic systems. The application of the designed magnetic tool allowsremoving the ferromagnetic objects from the well regardless of their shape, weight and position onthe bottom hole. Apart from that, the given tool may be used in the areas where the technology of work is related to drilling wells.

Parole chiave

  • fishing tool
  • magnetic system
  • permanent magnet
  • hoisting capacity
Accesso libero

Modified calculation model for loads of bearing systems for tricone roller bits

Pubblicato online: 07 Nov 2019
Pagine: 214 - 222

Astratto

Abstract

The article presents a modified calculation model of loads of cone bearing systems in tricone roller bits. The presented model includes the actual nature of the loads of a tricone roller bit and the effect of these loads on the construction of individual elements of the cone bearing systems. The presented calculation model was created in order to develop a computer program that allows the calculation and verification of structural parameters of cone bearing systems even at the stage of their initial design. It will allow an optimal selection of these parameters to geological properties of drilled rocks.

Parole chiave

  • drilling
  • drilling tools
  • tricone roller bit
  • cone bearings reaction calculation
Accesso libero

Asymmetrical mini disk tools – possibilities of use and directions for further development

Pubblicato online: 07 Nov 2019
Pagine: 223 - 232

Astratto

Abstract

The paper presents a new solution of asymmetrical mini disk tools for mining head of roadheader designed for hard and very hard rock mining. In the first part the benefits of disk tools used in TBM's and special tunneling machines were presented. Next part presents the results of works and laboratory tests performed for developing of new solution of asymmetrical mini disk tools. On the basis of these results new mining head equipped with mini disk tools with a complex trajectory was designed. The results of field tests with different constructional and material solutions of asymmetrical mini disk tools were presented. The directions for further development were described.

Parole chiave

  • hard rock
  • mechanical mining
  • disk tool
  • tool wear
  • efficiency
Accesso libero

Vibration analysis of a bucket wheel excavator boom using rayleigh’s damping model

Pubblicato online: 07 Nov 2019
Pagine: 233 - 241

Astratto

Abstract

For the ERc 1400-30/7 type bucket wheel excavator (BWE) used in various Romanian open pit mines, a virtual model of the boom was constructed in SolidWorks. On this model, the variable in time forces acting during the excavation process were simulated, and the time history analysis (time response) was performed. This dynamic time response analysis was performed for excavation of homogenous material only, considering the damping as being of Rayleigh’s type, where the damping matrix is a linear combination of the mass and stiffness matrices. Based on the conducted analysis, the displacements of the boom during excavation were observed.

Parole chiave

  • Bucket wheel excavator
  • damping
  • frequency response
  • modal analysis
  • resonance
Accesso libero

The influence of belt cover thickness on conveyor belt indentation rolling resistance

Pubblicato online: 07 Nov 2019
Pagine: 242 - 248

Astratto

Abstract

One of the methods for lowering of energy consumption in the drive mechanisms of long horizontal belt conveyors is to reduce belt indentation rolling resistances. These resistances depend on a number of factors: bottom cover properties, bottom cover thickness, belt design, idler diameter, load, speed and frequency at which the belt passes on the idler (indentation frequency), as well as on temperature. Determining how these factors influence indentation rolling resistances of various conveyor belt types is of great importance. The article describes a small-scale method for testing indentation rolling resistance. The method allows analysis of the influence of various factors on indentation rolling resistances. The article presents the results of tests on how belt indentation rolling resistance is influenced by thickness of the belt bottom cover. The tests were performed on belts with various core types.

Parole chiave

  • belt conveyors
  • conveyor belt
  • indentation rolling resistance
Accesso libero

Impact of selected parameters on the loading process with cutting screw heads

Pubblicato online: 07 Nov 2019
Pagine: 249 - 256

Astratto

Abstract

The article presents the influence of selected constructional and kinematic parameters of cutting screw heads on the loading process. The loading process is often referred to as an auxiliary process, because in the entire operation of the head the cutting process is considered dominant. Proper determination of the relationship between the cutting process and the loading process allows to understand how individual constructional and kinematic parameters of cutting heads and the cutting machine on which they are installed have an impact on each other. This knowledge gives potential users an opportunity to determine a reason for the lack of effective loading in the working conditions of a given wall. Besides construction and kinematic parameters, shielded loaders also have an impact on the loading process. The use of a shielded loader allows for improving the efficiency of the loading process, i.e. increasing the percentage of output loaded in the whole of the output transferred by the head.

Parole chiave

  • longwall shearer
  • loading of output
  • cutting screw head
Accesso libero

Supporting problems at an island mining face in shanxi, China. Case study based on field observation

Pubblicato online: 07 Nov 2019
Pagine: 257 - 267

Astratto

Abstract

In this paper, field observation is conducted in Fujiaao Coal Mine, Linfen city in Shanxi province, China, which is unique because of its island-typed mining layout. Firstly, geology, layout of the coal cutting face, supporting pattern are presented and details are also provided. Then the problems are discussed and analyzed based on existing bolting theories. It finds out the length of the cable bolt is too long, which requires long time to drill boreholes, whilst the effectiveness is limited due to the illogical combination between cable bolt function zone and rock bolt function zone. Also, the face place allocated to rock bolt is very likely to cause line contact between its edge and steel belt, thus the bearing force is tremendously weakened and solely determined by strength of belt. Furthermore, field observation proves the low active supporting effects to roof, thus leading obvious roof sink even without the disturbance of mining activity. Eventually, some solutions are proposed with the intention to improve the situation based on the economic and technical considerations, including bolting in humidity environment, rational cable bolt length, wise choice of face plate, and ways to increase pretension force. The viewpoints and comments of this study can be referred by practitioners in coal mines sharing same difficulties.

Parole chiave

  • coal mine support
  • bolt
  • support optimization
  • field observation
  • support failure
Accesso libero

Analytical investigations of the accuracy of the small diameter tool-joint tapered thread made by a lathe machining

Pubblicato online: 07 Nov 2019
Pagine: 268 - 276

Astratto

Abstract

The drill string consists of connected drill pipes and other elements. The connection is carried out by screwing of the drill string elements with the help of tool-joint tapered thread. The operational characteristics of the drill pipes depend of the manufacture precision of these tool-joints mostly. The accuracy of the thread is regulated by the accuracy of its profile and the accuracy of its pitch diameter value. The accuracy of the tapered thread manufacturing on the lathe in its depending on the values of the geometric parameters of the lathe tool and the values of deviations of its installation relatively to the workpiece axis is investigated. It is proved that for the tapered thread of form VI profile used for connection of drill pipes with the diameter from 30 mm to 44 mm the most influential factor, in relation to the accuracy of the thread profile is the value of the rake angle. Application of the rake angle value up to −5° according to the research data leads to a deviation from the specified profile of 0.3°, which is more than 35% of the declared standard tolerance on deviations from the profile. Also, the influence of the back rake angle value on the value of the deviation from the standard pitch diameter of the thread is proved. It is proved that the magnitude of the tangential displacement of the nose of the cutter relatively to the axis of the thread up to −0.2 mm can cause a deviation of the profile angle of 0.18°, which is 27% of the standard tolerance.

Parole chiave

  • drill string
  • back rake angle
  • tool-joint tapered thread
  • pitch diameter
  • lathe tool
Accesso libero

Directions for increasing conical picks’ durability

Pubblicato online: 07 Nov 2019
Pagine: 277 - 286

Astratto

Abstract

Conical picks are cutting tools used in many branches, in particular in the mining, road construction and building branch. Contact with the excavated face causes their constant wear, which is an unfavorable but unavoidable process. Milling heads of working machines are equipped with several dozen conical picks, and mining in abrasive or hardly accessible rocks can reduce their life to a few hours. It is in the interest of both users and producers to increase their durability, as tools replacement, apart from purchase and logistic costs, results in machine downtimes. In the article various solutions of conical picks, their construction, dimensions and materials used have been discussed. Technical procedures applied to increase the durability of conical picks and their regeneration as well as methods of extending the life of picks working in difficult conditions have been presented. Two author’s methods of extending the life of picks working in difficult conditions, covered by a patent application, have also been presented. The first solution involves ensuring an uninterrupted rotational movement of the pick in the holder. Patent claims include an innovative method of equipping the additional sleeve integrated with the holder with a rotational bearing, which enables a continuous rotation of the pick. The tool equipped with a bearing generates much lower movement resistance than the standard mounting. The holder is designed to mount classic commercial picks. What is important, the pick replacement does not require interfering with the bearing assembly. The second solution concerns the manner of protecting the working part of the pick by means of a special element made of an abrasion resisting material. This element is the pick tip, the geometry of which varies from the commonly applied posts made of sintered carbide. In this solution, the tip has a shape corresponding to the form of conical pick’s wear, which causes that its steel body does not wear. Moreover, there is a possibility of applying a mobile, rotational mounting of the tip to the body.

Parole chiave

  • conical picks
  • durability of tools
  • tool wear rate
  • pick equipped with a bearing
  • innovative solutions
Accesso libero

Determination of crushing energy during vibratory crushing

Pubblicato online: 07 Nov 2019
Pagine: 287 - 294

Astratto

Abstract

The paper presents a new method of determining the energy consumption for vibratory crushing. Using the laboratory vibratory jaw crusher with kinematic actuation of the jaws, the study of determining power consumption while crushing limestone and diabase was conducted. During the study, electrical energy used on the crushing process was measured as a function of changing design and kinematic parameters of the vibratory crusher, i.e.: jaws stroke, the outlet gap size and frequency of jaws vibration. The article presents program of the research, the laboratory test stand of the vibratory jaw crusher KW 40/1 and the test results. Comparing the theoretical crushing energy requirements, determined by the Bond hypothesis, with the values measured during tests a large differences were observed. Using the Bond hypothesis the Vibratory Work Indexes were determined for the tested materials. Their values are higher than limestone and diabase Work Indexes available in the known literatures. The explanation may be greater amount of energy transferred to the material during vibratory crushing, which results in much higher efficiency of the crushing process.

Parole chiave

  • crushing
  • vibratory crushing
  • crushing energy
Accesso libero

The use of simulation modeling in the design of elements of annular preventers

Pubblicato online: 07 Nov 2019
Pagine: 295 - 303

Astratto

Abstract

One of the main elements of control over wells in the process of their construction is the blowout equipment, which includes annular preventers. This also applies to wells that provide degassing of coal veins to reduce their gas dynamic activity. Modern technology of work requires expansion of the functionality of the sealing unit of the annular preventers with the simultaneous provision of its operational characteristics. Determining the necessary durability of seals for different operating modes is the study of their stress-strain state. The paper deals with the possibility of using simulation modeling in the annular preventers design situations and within the study of the armature geometry influence of the sealant fittings on its stress-strain state. The method of determining the material constants to realize the Mooney-Rivlin model has been proposed. The behavior of low-density rubber in software product has been described by the finite element method. The aggregation error of experimental and theoretical studies is 5%. Therefore, the preconditions and the possibility of using simulation modeling in the design of annular preventers devices with increased operational characteristics have been created and confirmed.

Parole chiave

  • simulation modelling
  • stress-strain state
  • annular preventer
Accesso libero

Modeling the movement of broadcast on the concentration table

Pubblicato online: 07 Nov 2019
Pagine: 304 - 311

Astratto

Abstract

The article attempts to analyze the work of the concentration table, on which the distribution of the material under investigation takes place. The efficiency of separation or otherwise enrichment depends on the drive that puts the concentration table plate into an asymmetrical reciprocating movement. The most frequently used solutions are concentration tables, on which the distribution of enriched material takes place in an aqueous medium commonly called wet enrichment. The AGH University of Science and Technology conducted simulation tests of material enrichment on a concentration table using the differences in friction coefficient commonly referred to as dry enrichment, i.e. without an additional medium. The article presents the effects of simulations that have been carried out for reference materials characterized by different friction coefficients and densities. The summary presents the analysis of obtained effects of computer simulations of material movement with different coefficients of friction. The simulations were carried out for variables: the frequency of vibrations of the concentration table and the angle of inclination of the table of the concentration table. It has been shown that it is possible to enrich the material by changing the above-mentioned operating parameters of the device.

Parole chiave

  • concentration table
  • coefficient of friction
  • enrichment
Accesso libero

Steel ropes in machines opencast mining

Pubblicato online: 07 Nov 2019
Pagine: 312 - 320

Astratto

Abstract

Basic opencast mining machines belong to the group of devices used to perform specific technological operations through mining, loading, transport up to the dumping of mining heaps. Machines work in EBD systems (Excavator-Belt-Dumping) and require high reliability. Multi-bucket excavators that require the use of rope systems in order to maintain stability and the possibility of mining at different levels. The paper focuses on issues related to rope work in multi-buckets excavators. On the basis of studies to assess the technical condition of the ropes identifies the causes of damage to ropes these machines. As a result of the research, final conclusions were formulated.

Parole chiave

  • wire rope
  • opencast mining
  • rope damage
Accesso libero

Small-scale testing of coal dust explosion propagation and relation to active barrier suppression systems

Pubblicato online: 07 Nov 2019
Pagine: 321 - 329

Astratto

Abstract

Coal dust explosions are a lethal threat to anyone working in an underground coal mine. Many coal mining countries including Australia and much of Europe already utilize passive barrier explosion suppressant systems but due to differences in ventilation patterns in the United States, simple passive systems such as the bagged barrier are not as cost effective. Active systems are triggered by properties of an explosion, such as pressure, heat, or light, and release or project a suppressant into the environment to suppress an explosion. To deploy an active system, the best sensor and suppressant release location and spacing must be determined; this must account for total system latency and explosive propagation speed. A 10:1 model of a longwall entry system has been developed to study the pressure wave propagation of coal dust explosions and consequent triggering of different suppressants. The scaled model, with its removable stoppings, allows multiple potential propagation pathways for an explosion to be repeatedly tested, different from typical straight shock tunnel tests. The layout also facilitates the placement of sensors and cameras to fully observe and document the tests. The pressure wave characteristics found at crosscuts and corners will aid in the development of active barrier trigger systems and spacing of suppressant release locations.

Parole chiave

  • coal dust
  • explosion
  • mine
  • active barrier
Accesso libero

Application of friction braking devices in drum shaft hoists

Pubblicato online: 07 Nov 2019
Pagine: 330 - 336

Astratto

Abstract

This article presents the problem of emergency braking in mining shaft hoists equipped with drum. The industrial applications of friction devices and mobile fender beams concerned only friction shaft hoists. For drum devices, it is necessary to use braking devices both in the shaft tower and its sump. The impact of such a solution on the construction of braking devices and on the braking process itself is the subject of the paper.

Parole chiave

  • shaft hoists
  • emergency braking
  • mobile fender beams
Accesso libero

The methodology of testing rotational resistances of the rollers under the operation load

Pubblicato online: 07 Nov 2019
Pagine: 337 - 343

Astratto

Abstract

One of the components that affects the energy consumption of belt conveyors is the rotational resistance of the rollers. In real conditions, the roller is subjected to loads not only radial but also axial, resulting from its cooperation with the belt and the way of installation on the conveyor. Knowledge of these resistances is important not only in the design of conveyors, but also in the improvement and search for new structural solutions of the rollers. The article presents an innovative stand dedicated to the study of rotational resistance of the rollers under operating load, its research capabilities and the results of preliminary tests.

Parole chiave

  • belt conveyor
  • roller
  • rotational resistances
  • operation load
Accesso libero

Systems of grained materials automated sampling from belt conveyors

Pubblicato online: 07 Nov 2019
Pagine: 344 - 352

Astratto

Abstract

The collection of representative samples of grained materials is necessary to determine the quality parameters of this material. This operation is carried out in difficult conditions (dustiness, noise, atmospheric precipitation), which is a nuisance to the staff taking samples and adversely affects accuracy. In addition, the quality of representative samples is affected by the care of personnel. Therefore, to ensure a higher quality of sampling operations and to eliminate the work of people in difficult conditions, systems have been developed for the automatic collection of representative samples from conveyor belts. The work gives examples of automatic sampling systems equipped with samplers and other auxiliary devices. The work contains descriptions of construction, classifications, an example of selection and examples of construction solutions for automatic sampling of grained materials.

Parole chiave

  • grained materials samplers
  • sample preparing
  • automated systems
Accesso libero

Equipment/machinery failure rate in hard coal mines

Pubblicato online: 07 Nov 2019
Pagine: 353 - 363

Astratto

Abstract

The main task of the maintenance services in hard coal mines is to ensure continuous operation of the equipment (machines). The measurable effect of these actions should be the reduction of maintenance costs of equipment (machinery) and thus the reduction of production costs – coal mining. The paper presents an issue of failure rate of technical measures applied in the mining process. In order to ensure greater efficiency and productivity, it is necessary to find the causes of the most frequent failures in this process and effectively counteract them. As a result of these activities, the production availability of machines/equipment involved in the mining process will increase. This will to a large extent ensure failure-free and uninterrupted progress, increase productivity and improve the quality of manufactured products, as well as reduce the operating costs of equipment (machines), and thus reduce production and product costs. This effect should consist mainly in the control of rational, safe and effective use and operation of equipment (machines) in the exploitation process. An algorithm implemented in one of the hard coal mines was presented. The technical condition of underground mining equipment was observed by periodical measurements of vibration parameters at selected points on the machine – measurements were conducted with a vibration pen. The aim of this research is to improve the reliability of technological process of a mining plant through its failure-free operation. In order to achieve this objective, i.e. the efficiency of a mining company, it is necessary to reduce its costs. The action that leads to this aim is a proper assessment of the technical condition with regard to the equipment used in technological process.

Parole chiave

  • mining machinery/equipment
  • failures
  • vibration pen
  • measurements

Part 2: Selected Organizational Problems in the Mining Industry, Editor: Krzysztof Kotwica

Accesso libero

Research on the coefficient of friction of becorit K22 and K25SB linings

Pubblicato online: 07 Nov 2019
Pagine: 367 - 375

Astratto

Abstract

The article presents the method and results of experimental tests of the coefficient of friction between a steel rope and friction lining. The BECORIT K22 and BECORIT K25SB floor coverings were tested. The tests were carried out in accordance with the recommendations of the new German standard: DIN 21258 – Lubricants and impregnating agents for drive discs and transport ropes in mining – safety and testing requirements. The authors in this article emphasize that the Becorit K22 and K25SB linings are used for the wheels of propeller drums of mining machines. Characterized by high coefficients of friction (μ ≥ 0.25), also in cases of extreme weather conditions on the surface. The chemical properties of BECORIT linings ensure their resistance to swelling in the event of different oils and lubricants as well as mine waters. The material of which the claddings are made ensures very good machinability during rolling of rope grooves with the use of turning or milling tools. BECORIT K22 plastic cladding is particularly suitable for use in hoisting machines, where the rope base forms a large overlap angle on the wheel grooves (max 1°31'), which causes its lateral wear faster. BECORIT K22 material in this case provides a higher service life compared to other materials. Due to the way they are mounted on the wheel, they are made as 1-piece (monolith) or bipartite. In this article, moreover, the structure and principle of operation of the measuring station on which the tests were carried out are presented in great detail.

Parole chiave

  • steel rope
  • coefficient of friction
  • lining
Accesso libero

The history of mining and metallurgy of metal ores in upper Silesia preserved in metallurgical waste dumps

Pubblicato online: 07 Nov 2019
Pagine: 376 - 383

Astratto

Abstract

The history of mining and metallurgy in Upper Silesia dates back to the early Middle Ages. Initially, appearing on the surface, calamine, i.e. oxidized zinc-lead ores, and limonite – iron ore were used. The development of mining technology allowed for exploitation of ore deposits at greater depths. It contributed to the intensive development of industry at the turn of the 19th and 20th centuries. At that time, one of the most important industrial settlements was today's Ruda Śląska. In its area, apart from hard coal mines, there were several forges processing locally exploited zinc, lead and iron ore. The testimony of the former mining and metallurgy, among others, is the dump, which is a remnant of the Hugo zinc smelter (1812-1932). Mineralogical and chemical analyzes of waste material collected on the dumping ground provide a lot of interesting information about the processed raw material.

Parole chiave

  • metal ores
  • metallurgical waste
  • waste dump
Accesso libero

The effect of temperature on the mechanical properties and workability of rock salt

Pubblicato online: 07 Nov 2019
Pagine: 384 - 393

Astratto

Abstract

Underground salt mining accounts for about 16 percent of the total salt production worldwide. When excavating salt rock, the cutters of the road header come into contact with the rock. This produces friction and, consequently, a rise in temperature. Generally, as temperature increases, salt gradually loses its plasticity. The extent of these alterations depends on the presence of other minerals in the rock. This paper presents the results of laboratory tests on regularly shaped samples of salt. An analysis was performed of the results of compressive, tensile and induced-shear strength, and of Young's modulus, Poisson's ratio, cuttability index and side chipping angle. The testing was conducted on samples with a temperature of about 20°C and samples heated to 50°C and 80°C. The tests showed that as temperature increased, so did compressive and tensile strength, and longitudinal and transverse strain of salt. The temperature increase caused, however, a decrease in shear strength. The cuttability index and the side chipping angle also decreased when the heated samples were being cut. The percentage changes in the parameters within the 60-degree temperature range were as high as several dozen percent.

Parole chiave

  • rock salt testing
  • mechanical salt parameters
  • salt cutability
  • temperature change of salt
Accesso libero

Effective utilization of man shift through sustainable workload testing for underground mining machine operators. An ergonomic based man-machine interface approach

Pubblicato online: 07 Nov 2019
Pagine: 394 - 403

Astratto

Abstract

Insight of man-machine interfaces during mining machine operations, better co-ordinance with human efficiencies and suitable workload selection in underground mining machine operation are the main viewpoints of the study. Total 12 side discharge loader (SDL) and load haul dumper (LHD) operators [N = 12] have been taken as participants of the study. The methodology is divided into two parts first part is devoted to measuring and analyzing workload response of machine operation with polar heart rate monitor. Machine operator’s heart rate ratio (HR ratio) for the whole shift is recorded and metabolic rate (MR) has been analyzed. Additionally, fatigue sustainability (FS) and degradation of muscle force (MF) are recorded for each work cycles up to exposure time period (ETP) of 360 minutes. In the second part of the methodology, based on the HR ratio recorded during the mining operation, a workload simulation study is undertaken on a treadmill at the surface following BRUCE protocol. At treadmill, based on HR ratio, workload achieved from mines along with three different workloads i.e. low, moderate and high has been tested. Differences in FS and degradation rate of MF after each workload experiment have been recorded. A result from the underground operational study shows that there is about 43.2% and 32.4% of decreasing MF for SDL and LHD operators after end of spells at mines. Additionally, a negative correlation (r = −0.99) is found between ETP and MF. The workload simulation study shows that there are significant differences between FS (p < 0.05) and MF (p < 0.05) data of mining and treadmill experiment with the same workload. In comparison to an underground operation, FS rate of low, moderate and high workload is recorded 60%, 35%, and 15% higher respectively than of mine workload. Higher FS rate may achieve due to availability of good environment. Among the tested workload only low kind of workload is found suitable for mining machinery job as degradation of MF is found significantly (p < 0.05) low and FS is found significantly (p < 0.01) high in this kind of workload. Therefore, it can be concluded that in mining machinery operation better to adopt low workload for effective utilization of man shift (EUMS) as it gives comparatively low MF degradation and better FS during continuous work.

Parole chiave

  • Fatigue sustainability (FS)
  • Muscle force (MF)
  • Heart rate ratio (HR ratio)
  • Exposure time period (ETP)
  • Effective utilization of man shift (EUMS)
  • Workload simulation
Accesso libero

Multiple-criteria decision-making for the choice of equipment in mining using the AHP method

Pubblicato online: 07 Nov 2019
Pagine: 404 - 415

Astratto

Abstract

Rational solution for mining equipment based on the use of haul trucks, excavators, wheel loaders and crunchers should result from thorough analysis of technical and economic issues – both cost-related and exploitational - which can have a crucial impact on the cost of minerals extraction. Moreover mining equipment should be selected with consideration for all vital parameters in specific exploitational conditions and even the exploiter’s preferences. This selection should consider hitherto disregarded criteria, such as mean availability and structure utilization of machinery systems with the aim to improve the same. Methodology presented in the paper illustrates practical application of MCDM and one particular method of this type – the Analytical Hierarchy Process (AHP) – for resolving the problem in specific exploitational conditions of mineral resource in surface mining AHP method covers a multi-criteria approach based on a compensation strategy to model preferences and assuming variant comparability. Taking into account the preferences of the evaluator, which determine the subjectivity of comparative evaluation, is the core of the multi-criteria approach, which treats such preferences Considering the above issues, the following paper is an attempt to develop new and universal criteria as well as a method of evaluation and selection of means of mining equipment for mineral resource surface mines.

Parole chiave

  • surface mining
  • mining equipment
  • utilisation
  • reliability parameters
  • Multiple-criteria decision-making (MCDM)
  • AHP
Accesso libero

Haul road roughness measurement using georeferenced truck vibration

Pubblicato online: 07 Nov 2019
Pagine: 416 - 423

Astratto

Abstract

Vehicle vibrations caused by poor haul road conditions create multiple negative effects for mines, including slower cycle times, increased maintenance, and operator injury. Vibration levels in vehicles result in part from road roughness. Mine roads are mainly constructed from in-pit materials that are more likely to deteriorate overtime and require frequent maintenance to maintain a smooth surface. The decision for when and where road maintenance is conducted is primarily based on visual inspections. This method can provide subjective, inaccurate, and delayed response to adverse conditions. The recent increase in vehicle telemetry data allows instant access to several types of data; mainly being used for haul fleet dispatching, collision avoidance, and geologic surveying, telemetry data has yet to see widespread use in road maintenance dispatching. This paper examines current road roughness characterization techniques and current telemetry data streams. An initial case study was conducted using vibration and Global Navigation Satellite System (GNSS) telemetry data to determine road roughness. Data from three haul trucks under normal operating conditions were collected over the course of a week. The results of this case study demonstrate localized vibration levels can be used to objectively identify rough roads. This can be further developed to dispatch road maintenance crews leading to overall reduced mining costs and increased operator health. The researches propose continuing to full scale test using data from an entire fleet and longer timeframe.

Parole chiave

  • Haul Road
  • Vibration
  • Operator Health
  • Road Maintenance
  • Big Data
Accesso libero

Experience of safety monitoring equipment application in the production processes of coal mines in Ukraine

Pubblicato online: 07 Nov 2019
Pagine: 424 - 431

Astratto

Abstract

The analysis of the state of security in the coal mines of Ukraine showed an urgent need for equipment to monitor the safety of production processes, identifying its shortcomings. The necessary regulatory requirements of the legislation of Ukraine on this issue have been considered in detail. A solution to the problem of creating modern equipment for monitoring the safety of production processes in coal mines through a new approach and a change in concept has been proposed.

Parole chiave

  • safety
  • coal mines
  • production process
  • control equipment
  • acceptable risk
Accesso libero

Analysis of measures to enhance energy efficiency and sustainable development of the gas transmission system of Ukraine

Pubblicato online: 07 Nov 2019
Pagine: 432 - 440

Astratto

Abstract

The requirements of the fundamental normative documents in Public Joint Stock Company “UKRTRANSGAS”, regulating activities in the sphere of energy efficiency, are considered and analyzed. The procedure for implementation of energy saving measures and controlling over their implementation is presented. The analysis of planned and actual indicators of fuel and energy resources saving has been carried out. The ways to improve energy efficiency with the use of renewable energy sources are given.

Parole chiave

  • energy efficiency
  • gas transmission system
  • fuel and energy resources
  • energy saving
  • sustainable development
Accesso libero

The strength problems in the operation of drum hoist cages

Pubblicato online: 07 Nov 2019
Pagine: 441 - 449

Astratto

Abstract

From information obtained from periodic surveys of cages used in the shaft of one of the Polish mines, it appears that the majority of registered damages of their supporting elements are fatigue cracks. These cracks are formed and develop mainly in main nodes or welds in the areas of their connection with the construction of the cage. In order to eliminate the causes of these damages and to increase the durability of cages, it will probably be necessary to reconstruct those fragments of the cages in which they occur. In order to determine loadings of load-bearing elements and the state of stress that arises in them during the operation of the device, a numerical model of the cage was developed. The results of the calculations made as well as their analysis form the basis for the assessment of the strength and durability of the load-bearing elements of the discussed cage. The key problem determining the durability of the structure – as shown by the analyzes carried out – is the method of constructing the connection of the strings with the appropriate elements of the cage. Changing this state requires significant structural changes of these nodes, which the authors of this study pointed out.

Parole chiave

  • Drum hoist cage
  • strength analysis
  • fatigue damage
Accesso libero

X-Ray CT inspection of subsurface areas of concretes exposed to fast flowing liquids

Pubblicato online: 07 Nov 2019
Pagine: 450 - 459

Astratto

Abstract

Concrete structures affected for a long time by flowing liquids are exposed to gradual erosion in surface layers caused by a combination of several degradation processes: abrasion, cavitation and chemical or bacterial impacts. Due to the complex phenomena and difficult-to-define initial and boundary conditions, the whole process cannot be easily simulated using the conventional computing tools. Laboratory experimental research is thus the most appropriate approach for the investigation of a suitable composition of concrete resistant to the flowing liquids. However, the methods used are often very time consuming and last even several years. High-speed water flows can be elegantly used for the acceleration of the mechanical simulation of a real situation. Several experiments on the effects of the high-speed water flows on concrete surfaces have been carried out. Using the X-Ray CT methods, subsurface structures of concretes exposed to the accelerated mechanical simulation of the erosion wear caused by fast flowing liquids were investigated and presented in the article. It has been shown that the simulation does not cause initiation of new fractures or cracks in the original concrete structure. The pure water flow mainly removes the hardened cement paste and reveals the aggregate grains. The water flow with abrasive particles disintegrates in greater depths and washes out entire aggregate grains, eventually amputates them and finally smoothens entire surface.

Parole chiave

  • erosion
  • concrete
  • fast flowing liquid
  • high-speed water jets
  • X-Ray CT
Accesso libero

Mining the sparking rocks in the context of most frequent cases of methane ignition

Pubblicato online: 07 Nov 2019
Pagine: 460 - 471

Astratto

Abstract

The article presents the principles of safe cutting of rocks prone to generate igniting methane sparks. A list of methane ignitions and explosions from the sparking of rocks caused by cutting with road header was given. Unusual case of methane ignition in conditions of full technical and technological protection of roadway development is discussed. In conclusions, the importance of an individual approach to geological and mining conditions in the case of the need to cut sparking rocks was emphasized.

Parole chiave

  • sparks
  • methane ignition
  • sparking rocks
  • protection
Accesso libero

The application of the integrated production assets management system in the Polish Mining Group Inc.

Pubblicato online: 07 Nov 2019
Pagine: 472 - 479

Astratto

Abstract

The management of the production assets in the Polish Mining Group Inc. is geared towards achieving strategic aims through the unification of the obtained machines/devices, their practical use while maintaining them in the proper technical condition, adhering to proper maintenance-renovation procedures, reserves optimization as well as final recycling with no re-use in the production cycle. The following paper presents the functioning of the IT support in the production assets management, geared towards the integration with other areas of technical and economic activities of the Group. The modular structure of the integrated IT system makes it possible to gradually implement the successive solutions functioning within the Group as well as in the surrounding local areas, ensuring the suitability to the current needs of the organization and the system users.

Parole chiave

  • production management
  • mining machinery
  • IT systems
Accesso libero

Application of fiber optic FBG techniques in analysis of strain in engineering machines

Pubblicato online: 07 Nov 2019
Pagine: 480 - 485

Astratto

Abstract

The paper presents the use of fiber optic FBG strain sensors for analysis of deformations of machines and devices including those used in mining techniques. FBG strain sensors have many advantages over classic strain measurements using electro resistance strain gauges. They are characterized by a significant measurement accuracy of up to 1 mm, a service life of up to 30 years, the possibility of measuring large deformations of up to 8%, significant fatigue life, the possibility of building measurement networks and, something extremely important in mining – intrinsic safety, because the operating medium is white light. The entire measurement system based on the optical interrogator was also discussed. It enables conducting both static and dynamic measurements. The results of the strain research for an engineering machine, in which the loads had exceeded 800 T, were reported.

Parole chiave

  • optical fiber sensors with FBG fiber Bragg grating
  • strains
  • engineering machines
Accesso libero

Modelling and simulation tests of a quadrocopter flying robot

Pubblicato online: 07 Nov 2019
Pagine: 486 - 495

Astratto

Abstract

In recent years, there has been a dynamic increase in the use of multirotor flying robots in various areas of economic and social life. Robots of this kind may be used in environmental research, after equipping them with an appropriate measuring systems. This includes taking measurements of various types of contaminants, such as: particulate matter (PM), various gases, noise and light pollution. To make this possible, it is necessary to conduct advanced model-simulation tests of the flying platform, analyse and determine the appropriate location for the measurement system. Most of the current research on methods and techniques of taking measurements on the flying platform does not take into account these issues. This work consists of two main parts: modeling and simulation tests, and experimental part carried out in laboratory conditions. As part of the work, quadrocopter dynamics equations have been developed and implemented in the Matlab/Simulink environment. The developed discrete mathematical model made it possible to simulate different robot maneuvers: upward, forward, sideways and rotation flight. In order to determine the required characteristics of the multicopter drive sets, a mobile dynamometer station was designed, constructed and programmed. The dynamometer allows, among others, to take measurements of thrust force, torque and rotational speed. The final stage of the work was the development of the numerical model and CFD calculations of the quadrocopter. In this part, distributions of the pressure fields and velocity for the robot's hover state were determined.

Parole chiave

  • quadrocopter
  • mathematical model
  • CFD simulation
Accesso libero

Revitalization and preservation of biodiversity. Focus on water bodies in the Cracow region

Pubblicato online: 07 Nov 2019
Pagine: 496 - 504

Astratto

Abstract

The studies included 2 water bodies in Cracow (Kraków), 6 water bodies in the commune of Zabierzów (Cracow County) and 4 in the commune of Niepołomice (Wieliczka County). The studies were carried out in June 2018 and May 2019. The ways on management of the water bodies were compared. Problems related to revitalization were identified. One of these problems is the preservation of biodiversity. In some cases revitalization reduces biodiversity. This can happen due to the liquidation or limitation of the reed bed zone. Such a situation was observed in the water bodied of Zelków and Karniowice (com. Zabierzów). Both have ornamental functions now. Removal of most of reed does not disturb mallards (Anas platyrhynchos), but makes it impossible to nest for other birds such as moorhen (Galinula chloropus). Moorhens were observed in two former fish ponds in Staniątki (com. Niepołomice) and in the pond of the Kaczeńcowa street. In one of them revitalization caused the diminishing of the water area, but did not change the character of the water body. Bird species were recorded at water bodies.

Parole chiave

  • ponds
  • revitalization
  • birds
  • biodiversity loss
Accesso libero

Modelling of global solar irradiance on sloped surfaces in climatic conditions of Kraków

Pubblicato online: 07 Nov 2019
Pagine: 505 - 514

Astratto

Abstract

The paper presents calculations of global solar irradiance on inclined surfaces of any orientation in the hourly time step. For computational purposes there were used the data from typical meteorological years (TMY) available in a form of text files on the website of the Ministry of Infrastructure and Development. Hourly solar global horizontal irradiance from measurements from the file for Kraków was used as input for five anisotropic models (Hay, Muneer, Reindl, Perez and Perez according to the new PN-EN ISO 52010-1 standard). Direct normal and diffuse horizontal and then global irradiances were calculated. To illustrate the effects of using different models, for the exemplary residential building, monthly solar heat gains and heating demand was determined according to the monthly method of PN-EN ISO 13790. In comparison to the solar data from the TMY, an average decrease in the value of solar gains amounted 37%, what resulted in an increase in the calculated heat demand of the building by 10%. This is very important since this change takes place without any modernisation works.

Parole chiave

  • Diffuse irradiance
  • anisotropic model
  • sloped surface
  • typical meteorological year
  • EN-ISO 52010-1
Accesso libero

Application of neural networks to the prediction of gas pollution of air

Pubblicato online: 07 Nov 2019
Pagine: 515 - 523

Astratto

Abstract

The issue of projecting the air pollution levels is quite essential from the viewpoint of the necessity to adopt specific prevention measures intended to reduce the pollution concentration in the air. One can apply certain machine learning methods, including neural networks, to build pollution concentration models. Neural networks are characterised by the fact that they can be used to solve the relevant problem when we face shortage of data, or we do not know the analytical relationship between input and output data. Consequently, neural networks can be applied in a number of problems. This paper discusses a possibility to apply neural networks to the prediction of selected gas concentrations in the air, based on the data originating from the measurement networks of the Polish State Environmental Monitoring System, combined with local meteorological data. Forecast results have been presented here for SO2, NO, NO2, and O3 in various locations. The author also discusses the accuracy of the respective forecasts and indicates the relevant contributing factors.

Parole chiave

  • air quality monitoring
  • air pollution
  • artificial neural networks
  • prediction
Accesso libero

Numerical investigation of the drag force reduction for homogeneous column of vehicles

Pubblicato online: 07 Nov 2019
Pagine: 524 - 531

Astratto

Abstract

This paper presents simulation studies on the aerodynamics of vehicles moving in an organized column. The object of research is a column that consist of three vehicles of the same type (homogeneous column). In this research geometry of Ford Transit was used. As a part of the studies, the air drag forces acting on individual vehicles were calculated. The results are presented in dimensionless drag coefficient. The influence of the distance between cars on the generated force was also determined. In the first stage of the work, a numerical model was developed based on the Ahmed body reference structure. The calculations were carried out for 9 different velocities. The obtained results of the drag coefficient were compared with the work of other authors. The applied turbulence model and parameters of the boundary layer were used to create a numerical model of a moving column of vehicles. Mesh independence for numerical model of van was verified. The Finite Volume Method was implemented in the ANSYS Fluent program and used for the calculations. The use of supercomputers was necessary due to the large size of the grid.

Parole chiave

  • aerodynamics
  • platooning
  • RANS
  • CFD
  • vehicles
Accesso libero

Opportunities of re-establishing underground mining in the borsod coal basin in north-eastern Hungary

Pubblicato online: 07 Nov 2019
Pagine: 532 - 540

Astratto

Abstract

Numerous underground coal mines were in operation in the Borsod coal basin in northeastern part of Hungary until the beginning of this century. The main area of utilization of the mined out coal beside power and heat generation was supplying households with fuel mostly for heating. In the beginning of the 1990ies the power plants in question were shut down for economic, environmental and technical reasons. Consequently all the mines were closed no later than 2004 and thousands of miners lost their jobs. A new perspective of coal mining can be enabled by other ways of utilization of coal, e.g. coal chemistry, etc. Safe and modern equipment and technology enabling high output, clean coal, furthermore high rate of yield are targeted. Opportunity of sustainable underground coal mining in the north-eastern part of Hungary is discussed in the paper. Analysis of the properties of coal deposits using three-dimensional (3D) modelling are used for considering opportunities of new mining operations. Models are being developed.

Parole chiave

  • underground mining
  • sustainability
  • clean coal
  • coal
Accesso libero

Green energy from a hybrid PV panels and wind turbine farm in Lebanon

Pubblicato online: 07 Nov 2019
Pagine: 541 - 548

Astratto

Abstract

The publication presents the results of analysis of green energy from a hybrid PV panels and wind turbine farm use in Lebanon. Electricity is one of the most critical problems in Lebanon. This publication presents an effective solution to this issue. It deals with the generation of green environment friendly electricity from photovoltaic (PV) panels and wind turbine. The genuine idea consists of placing these panels and turbines at the middle of the coastal highway since it is considered as a free land. The produced energy is fed directly to the off gird after being inverted using appropriate devices. The middle of the highway from Tyre to Sidon is considered to apply this research. The actual design consists of 15222 PV panels placed in pairs on a steel chassis among the entire 27300 m coastal distance, 2 meters wide and 7610 vertical axis wind turbines placed at a distance of 0.9 m away from each pair of PV panels. The total energy produced by the PV system is estimated to 7.4 GWh/y and 3.1 GWh/y at an average wind velocity of 4.04 m/s. In addition to its benefit from a free land, the produced energy is environment friendly since there is no carbon dioxide emission.

Parole chiave

  • Vertical Axis Wind Turbine
  • PV Panel
  • Carbon Dioxide
Accesso libero

Local benefits factored in utility scale wind energy for a remote location

Pubblicato online: 07 Nov 2019
Pagine: 549 - 554

Astratto

Abstract

The publication presents the results of analysis of possible local benefits factored in utility scale wind energy for a remote location. Electricity is one of the most vital problems on the Earth, thus utility scale wind and solar energy devices are boosting economic development. Energy demand is constantly increasing, despite efforts to ensure the energy efficiency of devices. People are looking for more energy and electricity to consume. Although wind energy is still being researched and improved, modern generation of wind energy is becoming more and more effective and desirable. This publication presents an effective solution to this issue. It deals with the generation of green environment friendly electricity from wind turbine. The genuine idea is to provide energy for remote location using onshore wind turbines. An analysis of the demand for energy at a remote location and electricity consumption was made to provide preliminary calculations of the wind farm. The number of required turbines is determined taking into account all related factors. A specific wind turbine has been selected and proposed to provide the necessary location with the necessary amount of energy. The analysis carried out showed that the produced energy is environment friendly since there is no carbon dioxide emission.

Parole chiave

  • Horizontal Axis Wind Turbine
  • Energy Generation
  • Greenhouse Gases
Accesso libero

Areas of industrial damages in upper Silesian industrial region versus recultivation or revitalization ?

Pubblicato online: 07 Nov 2019
Pagine: 555 - 561

Astratto

Abstract

Areas of industrial damages require elaborating efficient methods of reclamation and revitalization. A region of Poland, where process of degradation is particularly visible is Upper Silesian Industrial Region. Areas in the zone of many-years influence of Huta “Miasteczko Śląskie” are characterized by norm-exceeding concentration of heavy metals. The area in its direct surrounding was defined as industriogeneous desert. In 2017 on three designated testing grounds with diversified degree of contamination (see: map) of joint area of 1.5 ha, planted were jointly 6550 seedlings of chosen species of trees and bushes which were likely to survive in those conditions. In the first vegetative season, despite extremely long-lasting drought and high temperatures, the seedlings showed high survivability. It amounted 82% on industriogeneous desert (testing ground C) and 90-95% on forest testing grounds (A and B). Maples stood out among other trees with proper development and condition. The highest seedlings, especially mountain ash, birch and European red elder already in August had burnt top shoots and numerous necroses on leaves. Introduction of plants – hyperaccumulators of heavy metals, especially on industriogeneous desert will influence positively on condition and development of seedlings in future vegetative seasons.

Parole chiave

  • industriogeneous desert
  • reclamation of industrial areas
  • species tolerating contamination by heavy metals
Accesso libero

The use of mathematical modeling for the construction of a control system for a climate chamber

Pubblicato online: 07 Nov 2019
Pagine: 562 - 569

Astratto

Abstract

Due to the introduced political instruments, as well as the increase in awareness and standard of living, mechanical ventilation is becoming more and more popular in Poland. The growing market and standards force the manufacturers of air handling units to constantly improve the quality of their products. In order to verify the operation of these devices, it is necessary in a specially adapted for this object called the climate chamber. Due to the strict regulations regarding the working conditions of the said facilities, it is necessary to apply the processes of advanced control systems in the process of regulation. These processes are aimed at establishing stable parameters of air supplied to the tested objects, ventilation and air-conditioning units such as: temperature, humidity, flux. Due to the need for precise control and operation of the installation in industrial conditions, it was decided to use the PID controller. The article deals with the optimization of the heating and cooling system, because the temperature parameter was a problematic element in the proper operation of the climate chamber. Both the heating and cooling systems have been described and executive elements have been emphasized, thanks to which it was possible to control the flow of circulating factors. The procedure of selection and implementation of the regulator's settings and its influence on the operation of the climate chamber was also analyzed.

Parole chiave

  • ventilation
  • recuperation
  • climatic chamber
  • PID controller
  • optimization
Accesso libero

Wound image segmentation using clustering based algorithms

Pubblicato online: 07 Nov 2019
Pagine: 570 - 578

Astratto

Abstract

Classic methods of measurement and analysis of the wounds on the images are very time consuming and inaccurate. Automation of this process will improve measurement accuracy and speed up the process. Research is aimed to create an algorithm based on machine learning for automated segmentation based on clustering algorithms Methods. Algorithms used: SLIC (Simple Linear Iterative Clustering), Deep Embedded Clustering (that is based on artificial neural networks and k-means). Because of insufficient amount of labeled data, classification with artificial neural networks can't reach good results. Clustering, on the other hand is an unsupervised learning technique and doesn't need human interaction. Combination of traditional clustering methods for image segmentation with artificial neural networks leads to combination of advantages of both of them. Preliminary step to adapt Deep Embedded Clustering to work with bio-medical images is introduced and is based on SLIC algorithm for image segmentation. Segmentation with this method, after model training, leads to better results than with traditional SLIC.

Parole chiave

  • clustering
  • segmentation
  • machine learning
  • neural networks
  • wounds
Accesso libero

Intelligent system for monitoring the air pollution of the city in real time

Pubblicato online: 07 Nov 2019
Pagine: 579 - 588

Astratto

Abstract

The article reveals the theoretical foundations, types of pollutants, classification of monitoring and visualization systems of air pollution. A description of the design of the structure of the system is described, its components are described in detail, and the justification of the selected technologies is given. In general, the system consists of two parts: a device for collecting air pollution data and a site that displays these data in user-friendly form. Graphic images that display the appearance of a software product are also added.

Parole chiave

  • API – application programming interface
  • CAQI – Common Air Quality Index
  • EEA – European Environment Agency
Accesso libero

Numerical modeling of vertical axis wind turbine with air guides

Pubblicato online: 07 Nov 2019
Pagine: 589 - 595

Astratto

Abstract

Currently, obtaining energy from renewable sources, as never before, it has become one of the most important areas, but at the same time challenges in human activities. This is the effect of many factors simultaneously, including because of the media trumpeted the greenhouse effect, the necessity of reducing CO2 emissions, shrinking natural resources, and thus the desire to protect their welfare including conservation (including natural resources) for future generations. The paper presents the results of preliminary numerical analyzes of work for vertical axis wind turbines equipped with air guides. The carried out analyzes indicate the potential possibility of using this type of construction in practice. The obtained power factor value is higher than in classic wind turbines with a vertical axis. The conducted analyzes also indicate the possibility of optimizing the proposed constructional solution in order to increase efficiency of obtaining energy from the wind.

Parole chiave

  • Vertical axis wind turbine
  • numerical modeling
Accesso libero

Performance evaluation of continuous miner based underground mine operation system: An OEE based approach

Pubblicato online: 07 Nov 2019
Pagine: 596 - 603

Astratto

Abstract

CM is a globally renowned machine, designed to work as a mass production technology for underground coal. Different major coal producers across the globe are using this technology for decades to produce underground coal efficiently. India is also one of the major players globally in the arena of coal production and adopted this cutting edge technology since last decade by implementing at. few of the selective underground coal mining projects. Performance of CM technology is influenced by the geo-mining condition, fleets of other ancillary units and reliability of subsystems while implementation of this system depends largely on the extent of reserve. These aspects generate a scope of large scale research and development in this field. Overall Equipment Effectiveness (OEE) is the parameter to benchmark the equipment performance globally. OEE is the product of equipment availability, performance and product quality. This mining machine based paper focuses on the Overall Equipment Effectiveness (OEE) of the complete CM based operation to identify the vulnerable systems, which helps to design proper preventive maintenance programme. The CM based system is divided into few subsystems, such as; electrical, cutter, gathering arrangement, traction, hydraulic, chassis, feeder breaker, shuttle car, CM conveyor and out-bye conveyor. The downtime data used for this analysis is collected from an underground coal mine situated in the central part of India, belongs to one leading coal producing company of the country. From analysis it was found that, electrical systems and conveyors are among most vulnerable systems and deserves more care during maintenance. On the basis of these results recommendations are made to redesign the Preventive Maintenance Programme, in order to avoid the lower availability as well as lower OEE.

Parole chiave

  • Continuous Miner
  • Overall Equipment Effectiveness
  • Availability
  • Performance
  • Quality
  • Reliability
Accesso libero

Suppliers and their role in modern enterprise – Case study

Pubblicato online: 07 Nov 2019
Pagine: 604 - 612

Astratto

Abstract

For each company, the process of selecting and evaluating suppliers of both the components needed for production and the implementation of production process is a very important aspect of their business, as the selection of appropriate contractors has an impact on the quality of final product, which is offered to customers. Dynamically changing situation in the company’s environment causes that success is achieved by those companies which implement new solutions and tools in their relations with suppliers. One such solution may include the PN-EN ISO 9001:2015 standard, which requires the organization to evaluate and select suppliers, taking into account their ability to provide a product compliant with the organization’s requirements. This paper presents a proposal to supplement the procedure of supplier qualification in a selected company. Attention was drawn to the fact that it is necessary for the modern organization to have access to database of qualified suppliers, who at the time of arising demand are able to meet the requirements set for them. It is also important for the enterprise to have at least two qualified suppliers for the same component in its database. Such an approach results from the current market requirements. The paper is based on a case study as a recognized method of analyzing and discussing authentic situations applied in management sciences.

Parole chiave

  • quality
  • suppliers
  • supplier evaluation
  • ISO 9001 standard

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