An analysis of appropriateness of room-and-pillar method for extracting medium-thick inclined coal seams in Quang Ninh Coal Basin taking into account existing mining and geological conditions was carried out. Corresponding foreign experience of applying room-and-pillar method was considered in relation to the mines of Vietnam. Process flow sheet of first mining and extraction of medium-thick inclined coal seams by room-and-pillar method in complicated mining and geological conditions was developed, and optimal block length along the strike to provide the production safety and efficiency was determined.

Horizontal boreholes were adapted for using in mine dewatering systems. Efficient and economically sound application of this new method of dewatering requires using perforated or slotted pipes as filters when installing casing. Pressure drop along a horizontal borehole is a major factor that affects the borehole performance. The pressure drop is caused by four separate effects: wall friction, perforation roughness, inflow acceleration, and mixing effects. This paper is devoted to studying the effects of these two former factors in perforated or slotted pipes. Numerical analysis was carried out using different types of perforation holes and slots. The simulation model was constructed using ANSYS Fluent 14.5 software. The results showed that at high Reynolds number, roughness friction factor values in perforated pipes with circular holes are significantly higher than those in slotted pipes with axially elongated slots and slotted pipes with perpendicular (to pipe axis) slots.

In the conditions of Zhezkazgan copper deposit, exploited by underground method, ore losses in pillars left ranges from 12 to 25%, sometimes reaching 40%. During the period of Zhezkazgan deposit development, tens million tonnes of rich ores remained as the losses. Annual growing ore losses in various pillars, taking into account the growing overall ore production, is approximately equal to the annual productivity of the whole mine. Besides, high-grade copper ore sublayers has not yet involved in mining. Therefore, the search for the most effective methods of mining lost, off-balance, and waste ores is of paramount importance. One of such methods is in-situ leaching, which allows secondary extracting and maximum use of the mineral wealth. The research purpose was to experimentally study the processes of leaching of oxidized, mixed, and sulfide copper ores for old mined-out mines of Zhezkazgan deposit using various solvents. Leaching of oxidized and sulfide ores was carried out in 2 stages, while duration of the short-term tests was 35 days, and that of long-term ones, 294 days. For 10 months, 50–80% of copper can be leached from the oxidized-sulfide ores with particle size of below 20 mm. For the same period, 30–50% of copper was leached from chalcocite ore, whereas only 5–12% were extracted from bornite-chalcopyrite ore. This indicates low efficiency of leaching processing of the bornite-chalcopyrite ore. The best solvents in this case are sulfuric acid (5–10 g/l) and acidified iron (III) sulfate Fe₂(SO₄)₃ (5 g/l). Sulfuric acid consumption in the process of leaching and development of oxidizing processes decreases to 1.6–3.2 t/t of copper for the oxidized ore and to 2.5–4.1 t/t for the chalcocite ore that makes sulfuric acid leaching quite acceptable for these ores in terms of performance indicators.

In domestic practice of ore reserve estimation, including at the stage of Feasibility Study of conditions, ore intervals (composites) are determined taking into account the conditions. The conditions (Resource Estimation Parameters) include: cut-off grade (CoG) of a useful component; minimum thickness of ore body (minT); maximum allowable thickness of waste rock or substandard ore interlayers (maxTS), in-cluded in the ore body outline; minimum GT, calculated as the product of the cut-off grade by the minimum thickness of the ore body. Recently, in practice of ore reserve estimation, options for automating this process began to appear in specialized programs for processing geological and survey information. The main subject for developing automation for the process of creating ore intervals in the Micromine software and the topic of this paper is determining an ore body boundaries in the direction of thickness using the conditions. The situation under consideration arises in the absence of external geological boundaries and is typical for ore bodies of various morphologies: mineralized dykes, mineralized zones, stockworks, skarns, ore shoots, etc. Earlier, prior to the study of this problem, the composite calculations were implemented in the Micromine software for the following scenarios: along boreholes, by benches, by intervals, by geology, by grade. The software developers, starting from version 16, decided to implement the algorithm for calculating ore intervals based on the conditions as an independent method in a separate tab of the menu "Boreholes/Composite calculation/By grade (GKZ)". The main varieties (parameters) of the algorithm for building of ore intervals include: Less Stringent Rules and Strict Rules. General provisions for considering ordinary ore intervals, the similarities and differences in the operation of the main varieties (parameters) of the algorithm are given. Formally, for calculating ore intervals based on the conditions, it is necessary to apply the algorithm that takes into account all the conditions as fully as possible. In Micromine software, this algorithm consists in applying the Strict Rules with the “Deny adjacent ore intervals” option enabled. In practice, multivariance of "tie" and delineation of ore bodies based on the identified ore intervals takes place. The paper provides several formalized examples explaining the legitimacy of using one or another method for identifying ore intervals. Automation of the process of determining ore intervals leads to significant increase in the speed of data processing. The described algorithms allow for, subject to properly prepared and verified data available, to rapidly calculate and statistically process numerous options for obtaining ore intervals based on the input variable data of conditions: CoG, minT, maxTS, maxGT.

The main economic activity in the Jiu Valley is mining, which produces valuable mineral raw materials required for the region development and progress, representing the main link in the value producing chain. The majority of mining operations and other economic activities existing within the East Jiu basin produce negative environmental impact (more or less severe), as well as and positive effects such as those related to increasing employment, staff training, creating infrastructure, etc. In most cases, the negative impact of the human activities can be considerably mitigated or even completely eliminated through remedial measures, particularly through the environment rehabilitation in the affected areas. But if a water body is strongly affected by pollutants generated by the human activities, the pollution impact is especially heavy near the water body bottom, with significant negative changes of the aquatic ecosystems and impossibility of consumption and use of the water resources by the riparian population. The main objective of this paper consists in identification and description of all human activities presented within East Jiu basin and analysis of their impact on the river (and other water bodies) water quality. For assessing the East Jiu water quality and monitoring its variations with time, water quality index (WQI) was used, aggregating individual quality indicators (expressed in physical units) into a single unique water quality measure.

Ensuring effective development of industries consuming natural resources using scientific support requires creation of new materials with preset characteristics. This requires fundamental studies of physicochemical and thermodynamic properties of different chemical systems, in particular intermetallides (IM). At present, the study of aluminum-based metal systems with rare-earth metals is becoming especially important. The study is devoted to determining thermochemical characteristics of α-Al₁₁Ln₃, β-Al₁₁Ln₃ and Al₃Ln aluminum-lanthanide IM, by refining the values of their melting temperature and enthalpy using semiempirical and calculation methods, allowing obtaining sufficiently complete data sets on of melting temperature and enthalpy of the aluminum-rich IM compounds, finding ready demand in modern technology.

The paper considers assessing stability of the open pit southern wall when extracting exposed coal seam D₆. To assess the open pit southern wall stability when extracting exposed coal seams, modern research methods were used: the study of geology and analysis of the near-wall rock mass condition, creation of an observation station and monitoring, estimation of the southern near-wall rock mass stability, and analysis of the study findings. The pit southern wall is composed of clayey sediments up to 5 m thick, underlain by siltstone and mudstone up to 10-20 m thick, and a coal seam up to 5 m thick. Substantiation of the estimated strength characteristics of the rocks composing the open pit bench slopes, which determine the stress state of the slopes, arising under the effect of internal and external forces, has been performed. Instrumental observations produced by the station and the survey of fractures on the open pit wall enabled determining contours of the deformation zone and dimensions of the landslide prism. A geotechnical model of the near-wall rock mass was created, and stability assessment within the geological section along the line of maximum development depth was carried out. After implementing measures on surcharging slopes of the southern wall, the factor of safety amounts to: n_у =1.69−1.73 that indicates termination of the active phase of the wall deformation and confirms the wall stability.

Mining and geological information systems find growing application at modern mining enterprises, therefore, competent use of the software system functionality and development of appropriate techniques is very important and urgent issue. The paper describes the technique for medium-term planning of underground mining using the example of a copper deposit with applying room-and-pillar mining method in the Micromine mining and geological information system. Special attention is paid to taking into account various economic indicators when determining the sequence and methods of the deposit development. A list of data required for implementation of this technique when planning underground mining in the Micromine software product is presented. The use of the proposed technique allows at the planning stage to determine the main technical and economic indicators, as well as assess effectiveness of the selected direction of mining. The paper provides illustrations of the results of applying the developed technique, as well as examples of reporting documentation in the Micromine mining and geological information system.