Journal & Issues

Volume 29 (2023): Issue 3 (September 2023)

Volume 29 (2023): Issue 2 (June 2023)

Volume 29 (2023): Issue 1 (March 2023)

Volume 28 (2022): Issue 4 (December 2022)

Volume 28 (2022): Issue 3 (September 2022)

Volume 28 (2022): Issue 2 (June 2022)

Volume 28 (2022): Issue 1 (March 2022)

Volume 27 (2021): Issue 4 (December 2021)

Volume 27 (2021): Issue 3 (September 2021)

Volume 27 (2021): Issue 2 (June 2021)

Volume 27 (2021): Issue 1 (March 2021)

Journal Details
Format
Journal
eISSN
2247-8590
First Published
20 Mar 2021
Publication timeframe
4 times per year
Languages
English

Search

Volume 27 (2021): Issue 4 (December 2021)

Journal Details
Format
Journal
eISSN
2247-8590
First Published
20 Mar 2021
Publication timeframe
4 times per year
Languages
English

Search

0 Articles
Open Access

Restructuring Simulation of the Ventilation Network

Published Online: 01 Jan 2022
Page range: 1 - 6

Abstract

Abstract

Worldwide, the demand for raw materials and materials is constantly increasing, being proportional to the growth of the population. In this sense, the demand and production of solid fuels such as coal has grown steadily. At the level of the European Union, due to the restrictive coal extraction policy, production has steadily decreased and coal-producing countries have had to implement closure programs with strict deadlines. As mining networks shrink, there is an intensification of risk factors due to changes in the ventilation system. The paper presents the restructuring of a complex ventilation network.

Keywords

  • simulation
  • ventilation
  • coal extraction
  • mining
  • restructuring
Open Access

Investigations on the Stability of the Right Slope in the Area of Anina Wastewater Treatment Plant

Published Online: 01 Jan 2022
Page range: 7 - 18

Abstract

Abstract

Often, excavations of natural slopes are necessary in the site area for the construction of civil or industrial objectives. The execution of such works requires special attention, from the design phase, regarding the stability of the slope in the initial state, but also after excavation and identification, if necessary, of technical solutions to increase the stability reserve, thus ensuring the security during the execution of works but also of future constructions. Such a situation was encountered in the case of Anina Wastewater Treatment Plant (WWTP), when, in the absence of proper investigations of the slope to be excavated, there was a landslide that interrupted the site activities, and which, to some extent, jeopardized the objectives already built. In this context, at the level of 2015, slope stabilization works were designed and executed, works that proved to be insufficient. In 2021, it was necessary to conduct a new stability study in order to analyze the possibilities of continuing the construction of the treatment plant. This paper presents the results obtained during this study, as well as a series of conclusions and interpretations, regarding the technical condition of the slope in different hypotheses.

Keywords

  • consequent slide
  • stability
  • polygonal surface
  • right slope
Open Access

Improving the Stability of the Directional Room G 31-33, Horizon 210 - East, Ocnele Mari-Coceneṣti Salt Mine, By Reinforcement with Anchors and Shotcrete

Published Online: 01 Jan 2022
Page range: 19 - 27

Abstract

Abstract

The rock salt deposit from Ocnele Mari - Coceneşti was mined by the method with rooms and small square pillars, at the levels + 226m and + 210m. Although the saline is not deep, certain instability phenomena (cracks, exfoliations) have occurred in the resistance structures (pillars, ceilings), especially in the G31-33 directional room, horizon 210E. These instability phenomena were also highlighted following the 3D finite element numerical modelling. In order to prevent the degradation of the mining excavations and the resistance structures, the affected surfaces were supported with anchors and reinforced shotcrete. The ceiling of the consolidated section of the G31-33 directional room, horizon 210E is monitored by the systematic measurement, on topographic landmarks mounted on the ceiling, of the vertical and horizontal displacements.

Keywords

  • rock salt
  • rooms and pillars mining
  • stability
  • reinforcement
  • anchors
  • shotcrete
  • displacement
  • numerical model
  • finite element
Open Access

Analysis of a Replaceable Cutting Tooth of Bucket Chain Excavator

Published Online: 01 Jan 2022
Page range: 28 - 32

Abstract

Abstract

This paper briefly outlines the design of replaceable cutting teeth of bucket chain excavator, which are attached to a holder with a detachable joint. The description of the rock cutting process is very complex, so the investigation of the effect of lateral forces is complicated through cutting tests. We use accordingly numerical analysis to examine some segments of the cutting process. Our main objective is to present the finite element analysis of cutting teeth in which the linear increase of the lateral force is taken into consideration. The finite element analysis is a powerful technique, which is enabled to compute the stress and displacement distribution in cutting teeth. The simulation results have shown that the maximum stresses decrease if the lateral force increases. The geometry of the optimized cutting teeth will be safe under the given loading conditions.

Keywords

  • bucket chain excavator
  • cutting teeth
  • detachable joint
  • cutting load
  • FEA
Open Access

Simulation of the Vibrations Produced to the Human Body During Operation of the Bucket Wheel Excavators. A Case Study of ERc 1400-30/7 Type Excavator

Published Online: 01 Jan 2022
Page range: 33 - 49

Abstract

Abstract

The paper deals with the analysis of the dynamic response over time of the excavator boom during operation. For a start, we determined the variation in time of the forces acting on the rotor shaft, due to the excavation. These forces have high values and a slow variation over time, which depends on the rotation speed of the bucket wheel and the number of buckets installed on it. A virtual model of the BWE boom was proposed, for which the dynamic response in time due to the excavation forces was determined, for a point in the main cabin of the BWE. A virtual sensor has been attached to this point corresponding to seat of the operator. The simulation of the dynamic response over time was performed taking into account a global damping of 2% of the critical damping. The simulation was performed both for the excavation of a homogeneous material and for the case of a shock (a sudden appearance of an inclusion of hard material during the cutting of the homogeneous material).

Keywords

  • bucket wheel excavator (BWE)
  • dynamic time response
  • global damping
  • sensor
  • excavator operator
Open Access

Romanian Carbonate Rocks Cuttability Assessment Using Linear Cutting Tester

Published Online: 01 Jan 2022
Page range: 50 - 56

Abstract

Abstract

The paper presents the state-of-the-art on the microwave assisted mechanical rock cutting by presenting actual findings and tendencies in the field in international literature, and the activities performed during the intermediate stage and the results obtained by the team from the University of Petroşani as partner within the ERAMIN-ERANET-MIWACUT research project.

Keywords

  • microwave
  • excavation
  • carbonate rocks
  • point attack picks
  • mechanical properties
  • linear cutting test
Open Access

Considerations Regarding the Closure of the Mines in Valea Jiului

Published Online: 01 Jan 2022
Page range: 57 - 71

Abstract

Abstract

The paper, starting from a series of general considerations regarding the closure of a mine, makes an analysis, according to the available data, of the manner some of the mines in the Valea Jiului were closed. It is specified that the relatively short time since the closure of the first mine in the Valea Jiului (30 years) did not allow to highlight any mistakes / errors of closure, which would have significant repercussions on the surface land and, in general, on the environment. However, more or less serious problems have already been reported, which arose after the closure of some mines, problems that appear in the last part of this paper.

Keywords

  • mining
  • closure
  • Valea Jiului
Open Access

Effect of Beneficiation on the Characterization of Getso Kaolin

Published Online: 01 Jan 2022
Page range: 72 - 77

Abstract

Abstract

In their raw forms, clay minerals are found with a number of inherent impurities which make them unsuitable for most industrial applications. In order to overcome this problem and add value to clay minerals, beneficiation process is an indispensable solution. This study investigates effect of wet beneficiation process on the characteristics of a local clay mined from Getso village of Kano State, Nigeria. Mineralogical characterization of the clay was carried out using X-ray diffraction (XRD) analyzer. Chemical characterization of the clay was carried out using X-ray fluorescence analyzer. Physicochemical characterization of the clay was carried out using pH meter and density analysis conducted using density bottle. XRD analysis of Getso clay showed that the raw clay had 8 wt% kaolinite and 51% quartz. Wet beneficiation resulted into 53% improvement of the kaolinite content and 47% reduction of quartz impurity. The XRF analysis has shown that silica-alumina ratio of the raw Getso clay was 1.55 and this reduced to 1.49 after beneficiation. The physicochemical characterization of the clay has shown that Getso clay is neutral, the raw clay and beneficiated clay had average pH values of 7.5 and 7.3, respectively. Specific gravity values of the raw and beneficiated clay were 2.24 and 2.04, respectively. The beneficiation process had been effective as substantial increase in kaolinte content was observed and a reasonable decrese in the impurity contents was observed from the raw to the beneficiated clay. The Garnet content was completely reduced to zero while quartz, clinochlore and orthoclase were reduced by 24%, 9% and 13% respectively. The clay obtained after the beneficiation be serve as good raw material for production of whitewares, high grade ceramics in synthesis of zeolitic materials.

Keywords

  • Getso kaolin
  • Clay
  • XRD
  • pH
  • Specific gravity
Open Access

Mineralogical, Physicochemical and Morphological Characterization of Okpella Clay

Published Online: 01 Jan 2022
Page range: 78 - 82

Abstract

Abstract

Local clay mineral was mined from Okpella Town, Etsako Local Government Area of Edo State, Nigeria. Mineralogical characterization of the clay was carried out using X-ray diffraction analyzer. Chemical characterization of the clay was carried out using X-ray fluorescence analyzer and the pH analysis of the clay was carried out using pH meter. The mineralogical analysis revealed that the clay was majorly a dolomite mineral having 72% dolomite. The impurities present are 18% cristobalite, 4.1% garnet, 5% calcite and 1% quicklime. The pH analysis of the clay revealed that the clay was acidic having average pH value of 3.9. The pH determined for the 1:1, 1:2, 1:4, 1:8 and 1:10 samples were 3.61, 3.85, 3.85, 4.05 and 4.09, respectively.

Keywords

  • Okpella clay
  • characterization
  • XRD
  • XRF
  • SEM
  • pH
  • Specific gravity
0 Articles
Open Access

Restructuring Simulation of the Ventilation Network

Published Online: 01 Jan 2022
Page range: 1 - 6

Abstract

Abstract

Worldwide, the demand for raw materials and materials is constantly increasing, being proportional to the growth of the population. In this sense, the demand and production of solid fuels such as coal has grown steadily. At the level of the European Union, due to the restrictive coal extraction policy, production has steadily decreased and coal-producing countries have had to implement closure programs with strict deadlines. As mining networks shrink, there is an intensification of risk factors due to changes in the ventilation system. The paper presents the restructuring of a complex ventilation network.

Keywords

  • simulation
  • ventilation
  • coal extraction
  • mining
  • restructuring
Open Access

Investigations on the Stability of the Right Slope in the Area of Anina Wastewater Treatment Plant

Published Online: 01 Jan 2022
Page range: 7 - 18

Abstract

Abstract

Often, excavations of natural slopes are necessary in the site area for the construction of civil or industrial objectives. The execution of such works requires special attention, from the design phase, regarding the stability of the slope in the initial state, but also after excavation and identification, if necessary, of technical solutions to increase the stability reserve, thus ensuring the security during the execution of works but also of future constructions. Such a situation was encountered in the case of Anina Wastewater Treatment Plant (WWTP), when, in the absence of proper investigations of the slope to be excavated, there was a landslide that interrupted the site activities, and which, to some extent, jeopardized the objectives already built. In this context, at the level of 2015, slope stabilization works were designed and executed, works that proved to be insufficient. In 2021, it was necessary to conduct a new stability study in order to analyze the possibilities of continuing the construction of the treatment plant. This paper presents the results obtained during this study, as well as a series of conclusions and interpretations, regarding the technical condition of the slope in different hypotheses.

Keywords

  • consequent slide
  • stability
  • polygonal surface
  • right slope
Open Access

Improving the Stability of the Directional Room G 31-33, Horizon 210 - East, Ocnele Mari-Coceneṣti Salt Mine, By Reinforcement with Anchors and Shotcrete

Published Online: 01 Jan 2022
Page range: 19 - 27

Abstract

Abstract

The rock salt deposit from Ocnele Mari - Coceneşti was mined by the method with rooms and small square pillars, at the levels + 226m and + 210m. Although the saline is not deep, certain instability phenomena (cracks, exfoliations) have occurred in the resistance structures (pillars, ceilings), especially in the G31-33 directional room, horizon 210E. These instability phenomena were also highlighted following the 3D finite element numerical modelling. In order to prevent the degradation of the mining excavations and the resistance structures, the affected surfaces were supported with anchors and reinforced shotcrete. The ceiling of the consolidated section of the G31-33 directional room, horizon 210E is monitored by the systematic measurement, on topographic landmarks mounted on the ceiling, of the vertical and horizontal displacements.

Keywords

  • rock salt
  • rooms and pillars mining
  • stability
  • reinforcement
  • anchors
  • shotcrete
  • displacement
  • numerical model
  • finite element
Open Access

Analysis of a Replaceable Cutting Tooth of Bucket Chain Excavator

Published Online: 01 Jan 2022
Page range: 28 - 32

Abstract

Abstract

This paper briefly outlines the design of replaceable cutting teeth of bucket chain excavator, which are attached to a holder with a detachable joint. The description of the rock cutting process is very complex, so the investigation of the effect of lateral forces is complicated through cutting tests. We use accordingly numerical analysis to examine some segments of the cutting process. Our main objective is to present the finite element analysis of cutting teeth in which the linear increase of the lateral force is taken into consideration. The finite element analysis is a powerful technique, which is enabled to compute the stress and displacement distribution in cutting teeth. The simulation results have shown that the maximum stresses decrease if the lateral force increases. The geometry of the optimized cutting teeth will be safe under the given loading conditions.

Keywords

  • bucket chain excavator
  • cutting teeth
  • detachable joint
  • cutting load
  • FEA
Open Access

Simulation of the Vibrations Produced to the Human Body During Operation of the Bucket Wheel Excavators. A Case Study of ERc 1400-30/7 Type Excavator

Published Online: 01 Jan 2022
Page range: 33 - 49

Abstract

Abstract

The paper deals with the analysis of the dynamic response over time of the excavator boom during operation. For a start, we determined the variation in time of the forces acting on the rotor shaft, due to the excavation. These forces have high values and a slow variation over time, which depends on the rotation speed of the bucket wheel and the number of buckets installed on it. A virtual model of the BWE boom was proposed, for which the dynamic response in time due to the excavation forces was determined, for a point in the main cabin of the BWE. A virtual sensor has been attached to this point corresponding to seat of the operator. The simulation of the dynamic response over time was performed taking into account a global damping of 2% of the critical damping. The simulation was performed both for the excavation of a homogeneous material and for the case of a shock (a sudden appearance of an inclusion of hard material during the cutting of the homogeneous material).

Keywords

  • bucket wheel excavator (BWE)
  • dynamic time response
  • global damping
  • sensor
  • excavator operator
Open Access

Romanian Carbonate Rocks Cuttability Assessment Using Linear Cutting Tester

Published Online: 01 Jan 2022
Page range: 50 - 56

Abstract

Abstract

The paper presents the state-of-the-art on the microwave assisted mechanical rock cutting by presenting actual findings and tendencies in the field in international literature, and the activities performed during the intermediate stage and the results obtained by the team from the University of Petroşani as partner within the ERAMIN-ERANET-MIWACUT research project.

Keywords

  • microwave
  • excavation
  • carbonate rocks
  • point attack picks
  • mechanical properties
  • linear cutting test
Open Access

Considerations Regarding the Closure of the Mines in Valea Jiului

Published Online: 01 Jan 2022
Page range: 57 - 71

Abstract

Abstract

The paper, starting from a series of general considerations regarding the closure of a mine, makes an analysis, according to the available data, of the manner some of the mines in the Valea Jiului were closed. It is specified that the relatively short time since the closure of the first mine in the Valea Jiului (30 years) did not allow to highlight any mistakes / errors of closure, which would have significant repercussions on the surface land and, in general, on the environment. However, more or less serious problems have already been reported, which arose after the closure of some mines, problems that appear in the last part of this paper.

Keywords

  • mining
  • closure
  • Valea Jiului
Open Access

Effect of Beneficiation on the Characterization of Getso Kaolin

Published Online: 01 Jan 2022
Page range: 72 - 77

Abstract

Abstract

In their raw forms, clay minerals are found with a number of inherent impurities which make them unsuitable for most industrial applications. In order to overcome this problem and add value to clay minerals, beneficiation process is an indispensable solution. This study investigates effect of wet beneficiation process on the characteristics of a local clay mined from Getso village of Kano State, Nigeria. Mineralogical characterization of the clay was carried out using X-ray diffraction (XRD) analyzer. Chemical characterization of the clay was carried out using X-ray fluorescence analyzer. Physicochemical characterization of the clay was carried out using pH meter and density analysis conducted using density bottle. XRD analysis of Getso clay showed that the raw clay had 8 wt% kaolinite and 51% quartz. Wet beneficiation resulted into 53% improvement of the kaolinite content and 47% reduction of quartz impurity. The XRF analysis has shown that silica-alumina ratio of the raw Getso clay was 1.55 and this reduced to 1.49 after beneficiation. The physicochemical characterization of the clay has shown that Getso clay is neutral, the raw clay and beneficiated clay had average pH values of 7.5 and 7.3, respectively. Specific gravity values of the raw and beneficiated clay were 2.24 and 2.04, respectively. The beneficiation process had been effective as substantial increase in kaolinte content was observed and a reasonable decrese in the impurity contents was observed from the raw to the beneficiated clay. The Garnet content was completely reduced to zero while quartz, clinochlore and orthoclase were reduced by 24%, 9% and 13% respectively. The clay obtained after the beneficiation be serve as good raw material for production of whitewares, high grade ceramics in synthesis of zeolitic materials.

Keywords

  • Getso kaolin
  • Clay
  • XRD
  • pH
  • Specific gravity
Open Access

Mineralogical, Physicochemical and Morphological Characterization of Okpella Clay

Published Online: 01 Jan 2022
Page range: 78 - 82

Abstract

Abstract

Local clay mineral was mined from Okpella Town, Etsako Local Government Area of Edo State, Nigeria. Mineralogical characterization of the clay was carried out using X-ray diffraction analyzer. Chemical characterization of the clay was carried out using X-ray fluorescence analyzer and the pH analysis of the clay was carried out using pH meter. The mineralogical analysis revealed that the clay was majorly a dolomite mineral having 72% dolomite. The impurities present are 18% cristobalite, 4.1% garnet, 5% calcite and 1% quicklime. The pH analysis of the clay revealed that the clay was acidic having average pH value of 3.9. The pH determined for the 1:1, 1:2, 1:4, 1:8 and 1:10 samples were 3.61, 3.85, 3.85, 4.05 and 4.09, respectively.

Keywords

  • Okpella clay
  • characterization
  • XRD
  • XRF
  • SEM
  • pH
  • Specific gravity