MINERAL RESOURCES EXPLOITATION
The paper discusses the main disadvantages of strip and underground mining methods and possibilities of eliminating the disadvantages through introducing a combined technology of coal deposit mining. Combined coal mining technology is the method comprising elements of several geotechnologies, for example, underground and strip mining, as well as, possibly, underwater mining, borehole and other techniques of deposit mining. The combined coal mining technology provides for unified layout for opening, development, production and processing of reserves for the whole LoM on the basis of general technological solutions made in advance. Such complex solutions for opening and development of deposit reserves within the opencast and underground mining contour allows minimizing the volume of openings and reducing the time for commissioning, investment costs, as well as decreasing the costs for aerage, drainage, rock mass hauling and land reclamation. Substantiation of deposit opening options should comprehensively take into account technical, organizational, and economic factors [34–37]. Analysis of the options as exemplified by the Makar’evskoe coal deposit development in Kuzbass allows to conclude that the combined method is promising and promotes increasing optimal volumes of coal production, while reducing the deposit development time by about 15 %, and increase the net present value compared to underground and opencast mining options more than 5 times.
MINING ROCK PROPERTIES. ROCK MECHANICS AND GEOPHYSICS
The optimization of underground mining processes is carried out based on rational use of energy for obtaining preset broken ore size. The effective optimization requires correct assessment of the properties of the rock mass to be broken. Energy management requires assessment of rock mass stability decrease due to impact of natural and technogenic stresses. To make adjustments to the general energy management model, information on the rock mass structure is required to be obtained by geophysical methods. To optimize broken rock/ore size (to minimize oversized or excessively crushed mineral fraction yield during breaking), blasting energy application should be regulated and smart. The study is aimed at assessing the effectiveness of using geophysical methods for the prompt and correct assessment of rock and backfill mass condition during underground mining of mineral deposits. Decreasing stability of rock masses is assessed using the method of electrometric surveys in noncore exploratory boreholes. Rock mass stability study allowed revealing correlation and dependencies between the studied parameters. Effectiveness of using geophysical methods for differentiating natural and technogenic masses by degree of decreasing their stability due to geological and technogenic stresses. To determine the coefficient of decreasing rock mass stability based on rock apparent resistivity data, electrometric logging was used. This allowed to differentiate rock mass by the degree of decreasing rock mass stability based on the revealed dependency. The features of the geophysical survey components are described in details. The methodology and findings of the underground electric sounding using a sequential gradient electrode system at specific metal deposit are presented, including using theoretical curves and determining rock conductivity and the distance to workings. Besides, correctness of the geophysical method findings was assessed differentially. The assessment was prepared for decreasing rock mass stability based on electrometric logging data, and for advance outlining heterogeneity zones in rock masses by electric sounding along working walls. Based on findings of the conducted experimental work on revealing structural boundaries within rock mass, the method of electric sounding along working walls was recommended for application in practice. As for the studied borehole electric sounding application, the convergence of the experimental and theoretical curves is insufficient to recommend the method for practical application.
MINING MACHINERY, TRANSPORT, AND MECHANICAL ENGINEERING
Mining transport systems largely determine effectiveness of mining enterprises. The study aim is developing new technical solutions for progressive mining transport systems based on the harmonization of technological solutions and equipment. The aim is achieved through the introduction of new mine transport designs compatible with tunneling machinery, enabling change from cyclic concept of a mining enterprise activity to in-line system concept. The option is considered on development of designs of steeply inclined and curving conveyors in transport workings, including overhead and floor pipe belt conveyors and airdraulic pipeline systems for delivering lump ore from the face to the surface in the mine. At the same time, the basis of the proposed technology and equipment is the method of contactless hard rock breaking by using hydroimpulsive facilities. The proposed solutions allow decreasing mineral mining and processing capital and operating costs.
GEOLOGY OF MINERAL DEPOSITS
Material characteristics of placer gold and geological and geomorphological features of placercontaining watercourses allow revealing the type of source that formed the placer. The studied area (the middle reach of theAdychaRiver, Verkhoyansk District, Yakutia) is characterized by highly developed placer gold mineralization both in ancient terrace sediments and high-order watercourses. The significant placer gold mineralization in the high-order watercourses, at very limited number of known bedrock gold deposits suggests the presence of not yet discovered bedrock gold mineralization. Revealing the type of sources of placer gold in young high-order watercourses allows to create prognostic and prospecting models for both potential placer and primary (vein) ore occurrences. The purpose of the study is to compile a logical-information algorithm, which, based on the most significant material and geological-geomorphological factors, will enable revealing the type of placer gold source and the possibility of its location discovery and probability of gold transportation continuation from the source. The study result is presented by a program (the Python programming language) that characterizes the type of placer gold source based on gold grain rounding degree, the presence of gold intergrowths with other minerals and the presence of heavy fraction. Assessment of the possibility of placer gold source location determination is based on geological and geomorphological factors: watercourse order, the type of placer, and spatial association with terraces of ancient erosion levels. The study of well-known gold placers using the created program allowed revealing gold placers with supposedly primary gold source and other ones with the source in the form of a natural intermediate gold concentrator. A map of exogenous gold mineralization with forecast elements was also created, presenting areas promising for revealing primary gold mineralization (areas of presence of high-order watercourses with gold mineralization source) and areas of high-order watercourses promising for discovering gold placers (identified by analogy (in geological and geomorphological position) with watercourses with the known source in the form of natural intermediate gold concentrator.
The Chernogorsky jewelry scapolite deposit is located in the eastern part of the Central Pamir tectonic zone (the eastern part of the Republicof Tajikistan). A geochemical anomaly of cobalt and nickel of more than 55,000 m2was identified in the territory of the deposit. Within the anomaly, the metals were detected in all minerals, 95% of which belong to non-metallic minerals: olivine, enstatite, hornblende, phlogopite, calcite, dolomite, plagioclase, scapolite, potassium feldspar, nepheline, and sodalite. The deposit ore minerals comprise ilmenite, titanite, rutile, magnetite, hematite, pentlandite, pyrrhotite, and pyrite. The cobalt content is more than 20 times higher than its crustal abundance, and that of nickel is 10 times above its crustal abundance. It is recommended that the Ministry of Geology and the Ministry of Industry of the Republicof Tajikistanconduct the prospect evaluation to assess the prognostic resource potential for these elements. This allows to consider the deposit rocks (harzburgite, amphibolite and albitite) as cobalt-nickel geochemical anomaly. This anomaly should be the subject of greenfieldexploration for the elements. The deposit monomineral category may change to complex polymineral and polymetal category. This will significantly increase its investment attractiveness and economic feasibility.
SAFETY IN MINING AND PROCESSING INDUSTRY AND ENVIRONMENTAL PROTECTION
Mining and sustainable development may be compatible with the priority of measures to reduce impacts on the major ecosystems with severe consequences for the future generations. Infiltration of contaminated water into soils/rocks due to activity of different sectors of mining industry causes increasing concentration of minor and major deleterious elements in natural environment, forcing an economic operator to implement the best available techniques to solve severe environmental problems. The research is aimed at determining heavy metal contents in tailings storage facilities of coal mining operations in the eastern part of JiuValley, revealing mechanism of interaction of the TSF infiltrate with EastJiuRiver, as well as assessing the impact of the TSF on quality of the natural environment. One more aim of the research was to determine the ways by which the TSF components produce negative impact on the soils and surface waters. The obtained results can be fundamental basis for the future researches in the field of closing and maintaining the mining activities in JiuValleyand the land reclamation.
In mining industry safety is top priority. There is a request for safety management, risk prevention and operator training. Operator fatigue and distraction leads to dangerous situations. The paper is aimed at reviewing the issues of fatigued or distracted driver operation. This is achieved through creating models in occupational safety strategies. Hereafter the implementation of fatigue and distraction control system within a pilot project is discussed. The pilot project was aimed at collecting realistic operation data from mining industry in Europe. Caterpillar Inc. offers a solution called Driver Safety System (DSS). When driver’s micro-sleep is detected, the system alerts operator through different alarms directly. Dangerous events are also recorded and classified individually in 24/7 monitoring centre. The DSS was tested at European limestone open pit mine with typical working regime. This paper discusses theories, results and transferable insights of the study.