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

The ventilation networks are associated with the set of underground mining works used for the extraction of useful mineral substances. Over time, the ventilation networks involve a change in the structure due to either the expansion or restriction of the mining works structure. For the establishment of air flows at the level of each active mining work, specialized programs are used at international level. These programs allow the modelling and solving of complex ventilation networks. The most advanced specialized programs are those from the VENTSIM range. The paper presents the updating of the ventilation network related to Livezeni mine, with the help of the VENTSIM program.

In order to ensure the microclimate conditions for the exploitation of useful mineral substances underground, it is necessary to ensure the control of gas emissions from the field and from the exploited space. For this it is necessary to ensure a balanced air flow at the level of each active mining work in order to dilute the gases. Specialized programs are used to ensure the optimal distribution of air flows at the level of each mining work. The paper presents the modelling and solving of the ventilation network related to Livezeni Mine with the help of the 3D CANVENT program.

The underground mining of the rock salt deposit from Slănic started in 1665, with the Old Mines and continued in 1970, with Victoria Mine, then in 1993, with Cantacuzino Mine. The mining method applied at Victoria and Cantacuzino mines was the one with small rooms and square pillars, with which over 9.7 million m3 of rock salt were extracted. This very large volume of underground mining voids led to the convergence of the underground excavations and thus to the deformation of the surface. This article presents the analysis of the measurements of surface displacement and the prediction of its subsidence over time. Also, the main factors that contributed to the deformation of the surface are analyzed, namely: the dimensions of the underground voids, the mining depth, the geomechanical characteristics, the tectonics and microtectonics of the deposit, the hydrogeology and the effect of blasting.

The factors that influence the strength characteristics of rocks can be different in nature, being divided into external and internal factors. The mechanical properties of hard rocks are a result of geological, physical and chemical factors. In order to highlight the physical parameters that influence the strength characteristics of the rocks, in this paper there were analyzed six types of volcanic magmatic rocks such as andesites. In terms of stress behavior, rocks are directly influenced by their physical properties, such as volumetric density, porosity, compactness, moisture and the degree of alteration of mineral components. For this purpose, several sets of tests were performed to determine the physical and mechanical characteristics of the rocks, based on which it was possible to analyze how the physical parameters influence the strength characteristics.

Given the possibilities offered by PIV systems, it was considered appropriate to test them in the study of the formation of explosive atmospheres. In this sense, within the INCD INSEMEX Petroșani laboratories, a test stand was created subject to the conditions of applying PIV techniques. Thus, this stand was built of transparent materials, having the possibility to introduce, in the inner volume, the suspended particles and the combustible gas, being at the same time able to be sectioned by the light plane generated by a laser source and to provide the recording conditions using a CMOS camera. The physical experiments concerned both the situation of a normal atmosphere inside the test stand and the situations of the appearance of a fuel gas leak and an efficient source of initiation of the formed explosive atmosphere.

This paper deals with the analysis of two cases of coal self-heating from two longwall mining within the coal exploitations belonging to Complexul Energetic Hunedoara, phenomena that started similarly but later evolved differently, as a result of prevention methods applied or not applied in each case. For the analysis of these self-heating phenomena, the data collected after the occurrence of the first signs were used, respectively the emission of carbon monoxide in the longwall mining area, until the moment of desertion and closure of the longwall with dams in the first case and eradication of the phenomenon in the second case. By analyzing in parallel the two cases, several conclusions are drawn which may help to counteract these types of phenomena that may occur in the longwall exploited in similar conditions.

In this article an impact assessment is carried out, generated by activities in the energy sector related to Rovinari mining area. Energy-related activities in this area are carried out by open pit mining activities in the context of Tismana, Roșia, Pinoasa, Peşteana and Rovinari locations and Rovinari thermal power plant. Some information that has formed the input for the author’s approach has been provided by SC. Complexul Energetic Oltenia SA (CEO) and S.C. Institute of Scientific Research, Technological Engineering and Mine Designs on Lignite S.A. Craiova (ICSITPML) which has been processed, analysed and used for the presented environmental impact assessment. Two methods from specialized studies have been used for the impact assessment, namely: the Matrix Method for Rapid Impact Assessment (MERI) and the Method for Integrated Quantitative Impact and Risk Assessment of Environmental Pollution (EIRM). Based on the analysis carried out, it can be concluded that the activity in this sector does not lead to significant negative effects strictly associated with it.

The impact of extracting lignite in Lupoaia open pit over waters is local and regional, and temporary. The hydrographic network in Lupoaia open pit depends on River Motru, with its afluents, Ploștina and Lupoița Valley Rivers. The aquifers are to be found in the coal layers V-XII, mainly of sands formation. The impact over water in Lupoaia consists of water pollution and of changes in both the quality and the quantity of ground and surface waters. The surface waters are polluted resulting in industrial wastewaters, household wastewaters and waste rainwater. The wastewater is polluted within maximum admitted limits. The quality of groundwaters is influenced and modified by extracting coal resulting in the extinction of some aquifers. Environmental risks that can occur when extracting lignite are water floods, landslides, disasters which can be prevented by building guard channels around the open pit. The actions for reducing the impact are, in general, accomplished through monitoring both the water pollutants and the morphological changes caused by extracting lignite. That is why wastewater treatment plants must function. The impact of the activity in Lupoaia open pit over the hydrographic net of the area is to be observed during the entire extracting period, and monitoring this activity is highly demanded by the European environmental protection laws.

Starting from the fact that in the mining industry and in general in the field of underground constructions, the topographic activity, regardless of which of its manifestations, conditions and substantiates the achievement of economic and technological objectives, implicitly resulting in the dependence between topographic precision and qualitative and quantitative performance of mining. The level at which the professional responsibility of the topographic activity, as a whole is engaged in the achievement of some proposed objectives, depends on the framework resulting from the technological complexity of the mining activity in the conditions of its restructuring and efficiency. Spatial representations of useful mineral deposits in the earth's crust, which meet the quality conditions necessary for the design of underground mining works, can be used to choose the most efficient methods of opening, preparation and exploitation of useful mineral deposits. These analyzes are the basis for the realization of underground topographic networks that have a precise connection with the topographic base at the surface. The use of stereographic projection and stereographic networks can be achieved by faithfully representing the tectonics and positioning of deposits of useful mineral matter inside the earth's crust.

The underground topographic works of elevating and drawing are necessary for the execution of underground works (mining, hydrotechnics, communications, etc.) Fulfilling these works efficiently and safely requires an advance study for the precisions in topographic support routes and networks. This paper aims to establish the share distribution correlated with the underground works distribution.