The open method of solid minerals winning occupies a significant place in the total opening of the mining complex deposits of the Republic of Kazakhstan. In the energy band, a prominent role belongs to the Ekibastuz coal basin, where a number of large coal strip mine operates. The level of subsurface, equal parts of spoil bank of the external and internal stripping after a while lead to complex problems of ensuring the stability and safety of mining operations. The location of large external rock dumps on the bead surface has a negative effect on the stability of the latter. The purpose of the work was to establish the degree of the external rock dump influence located on the bead surface on the stability of adjacent rock mass of the coalmine depending on the distance of the dump to the upper edge of the side. There was numerical simulation of stress-strain state of adjacent rock mass under action of distributed load from rock dump carried out. It has been shown that studies of any point stability of the array from this type of load should be carried out on the basis of elasticity and the use of the finite element method theory implemented in packages of programs oriented specifically to scientific and engineering applications. There are the methodology and results of numerical modeling of quantitative assessments of various sections stability of the side loaded with an external rock dump with a height of 160m presented on the example of «Ekibastuz» coal mine. Based on a certain theory of rock strength and the criteria for their discontinuity, limit estimates of the critical distance of the external rock dump from the upper edge of the side were obtained, at which the latter may lose stability.
The aim of the study is to optimize technological solutions to reduce the cost of building a filling array, which remains one of the most pressing issues in the development of ore deposits by underground method. To achieve this goal, a comprehensive research method is used, which includes, first of all, a generalization and analysis of the practice of backfilling of enterprises, geotechnological design in relation to the storey-chamber development system and a feasibility study of optimization solutions at the level of expert assessment using the capabilities of engineering forecasting. Laying works with underground technology of mining of mineral deposits are the most costly, in connection with which research is carried out in order to develop ways to reduce the cost of repayment of the worked-out area. Through a systematic review and critical analysis of existing backfill technologies, the technical feasibility and economic feasibility of combining a hardening mixture and waste rock within a single repayable object has been identified, which provides a radical reduction in the proportion of hardening backfill. In the article offered to the reader’s attention, a variant of the combined array design and the technology of its formation are proposed. A variant of mechanization of the process of erection of the combined massif using specialized dump trucks is provided. This method of forming a combined filling mass allows reducing the volume of the hardening mixture in the total volume of the worked out space of the chambers by not a third. In connection with the complex mechanism of the formation of the combined filling massif, the work considers various options for the discharge of rock into the goaf, which differ in the number of points of discharge of the ingredients of filling materials into the goaf. Based on geotechnological design and mathematical modeling of the formation of a filling massif, it is certain that to increase the efficiency of filling the worked-out chamber space, two points of controlled rock discharge are necessary. The study identified ways to reduce the cost of controlling rock pressure in specific conditions by combining hardening mixture and waste rock for filling voids with a reduction in the proportion of hardening filling up to 50%. A variant of the combined massif construction with mechanization of the massif erection process using specialized dump trucks can significantly reduce the volume of the hardening mixture.
The purpose work. Substantiation and selection of a safe and effective option of mining technology of the experimental block in the pilot industrial mining of the Skalistoe deposit. Method of research. Analysis and synthesis of project solutions, experience in mining inclined low-thickness ore bodies, economic and mathematical modeling and optimization of the parameters of options mining systems in the conditions of the experimental block. Results of research. As a result of research it was established: - the sublevel caving mining system with the parameters adopted in the project does not guarantee the completeness of the extraction of reserves and the effectiveness of mining operations. Project indicators of extraction by sublevel caving technology with frontal ore drawing are overestimated and difficult to achieve in these geological and technical conditions (combination of low thickness and angle of ore body); project scheme for the delivery and transportation of rock mass seems impractical due to the significant volume of heading workings and increased transportation costs; - eight technically rational options of various mining systems were constructed, most relevant to the geological and technical conditions of the deposit. Five variants of the sublevel chamber system and pillar caving, a project variant of sublevel caving technology with frontal ore drawing and two options flat-back cut-and-fill system were considered; - for mining the Skalistoe deposit, according to the results of economic and mathematical modeling, optimal by the criterion of profit per 1 ton of balance reserves of ore is a option of the technology of chamber extraction with dual chambers, frontal drawing of ore by remote-controlled load-haul-dump machine and subsequent pillars caving, as having the greatest profit; - the calculations justified stable spans of dual chambers (25.3 m) and the width of panel pillars (3 m). With an allowable span of 25.3 m, the roof of the dual chambers will be stable with a safety factor of 1.41, and a panel pillar with a width of 3 m has a sufficient margin of safety (more than 1.6) in the whole range of ore body thickness variation; - the proposed scheme of delivery and transportation of rock mass, which allows to reduce the volume of tunnel works by 26% and the average length of transportation by 10-15% compared with the project. Findings. Developed in the process of modernization the technology sublevel chamber system with double-chamber, compared with the project technology, it is possible to significantly increase the efficiency of mining of the low thickness deposit of rich ores Skalistoe by reducing the specific volume of preparatory-rifled work by 34%, the cost of mined ore by 12%, losses and ore dilution – by 2 and 2.9 times, respectively.
Introduction. Currently used grinding machines, among which drum mills are the most widely used, have a low efficiency, are bulky, are characterized by low specific productivity, significant consumption of steel for grinding bodies and lining, high noise level, and high energy consumption of the grinding process. The most promising devices of a new type that can effectively perform grinding operations at high technological rates are centrifugal mills. The centrifugal mill developed at SKGMI operates on the principle of self-grinding of pieces and particles of crushed mineral raw materials, when they collide and RUB in a mobile toroidal flow formed when the material moves between a rotating Cup-shaped rotor, a fixed body and the overlying layers of the crushed material. Grinding occurs due to the appearance of a gradient of particle velocities over the working body, due to their impact and, to a greater extent, abrasion. The tests of these mills for grinding various materials have shown high efficiency in operation, but until now, the issues of determining the physical and mechanical properties of the crushed material based on the establishment of the particle opening mechanism remain unresolved. The purpose of the tests. Determination of the physical and mechanical properties of the crushed material in a centrifugal mill based on the establishment of the particle opening mechanism. Test procedure. To solve this problem, a vertical centrifugal mill MC-600 with a rotor diameter of 600 mm was used. Tests of the centrifugal mill were carried out according to the following method. The speed of rotation of the rotor was 4.8 and 8.4 s-1, the height of the material column above the rotor was at the level of 250 and 350 mm; 6 radial ribs were installed in the rotor cavity of the mill. The time of each test was 4 hours. The tests were repeated 3–5 times for each mode of operation of the mill. Quartz was used as a reference material for determining the relative pulverizability coefficient. The research was carried out in the production conditions of the Izhevsk machinebuilding plant during the regeneration of spent molding quartz mixtures. Pieces of a liquid-glass mixture based on quartz sand with strength of 1.3 MPa and 4.25 MPa were used as the crushed material. The crushed material was dispersed according to the standard method for each hour of operation of the mill. Samples were taken in the size class -0.200 + 0.074 mm for their fractional analysis by size. Test result. 1. It was Found that the maximum productivity of a centrifugal mill when grinding pieces of material with a strength of 1.3 MPa was achieved with a loading weight of 90– 100 kg, and with a strength of 4.25 MPa – 100–110 kg, which indicates the need to create an increased normal pressure of the layers of crushed material located above the mill rotor. It was found that the maximum productivity of a centrifugal mill when grinding pieces of material with a strength of 1.3 MPa and a rotor rotation frequency of 8.4 s-1 was 13.16 t/h, and when grinding pieces of material with a strength of 4.25 MPa – 10.0 t/h. 2. The Dependence of power consumption on the weight of the mill load and the rotor speed increases when the load weight is more than 100 kg. 3. The Highest fraction content of class -0.4 +0.16 mm is 72.14 %, and the content of class -0.074 mm is 3.9 %, i.e. there is no re-grinding of the source material. 4. The specific productivity of the centrifugal mill for the newly formed calculated size classes -0.074 mm and -0.200 mm was 1.28 t/h and 13.0 t/h, respectively. 5. Microscopic study of anshlifov showed that quartz grains in the crushed material mostly have a rounded shape, on average 90–95 % of the grains. In the initial material, about 90% of quartz joints with a binder, and in the crushed material
The Greater Caucasus experienced repeated glaciation during the Quaternary (early, middle, upper Pleistocene, late Glacial, and late Holocene), which occurred under changing climatic conditions and differentiated tectonic movements. These glaciations, of course, are associated with changes in terrain, the formation of new deposits, transgressions and regressions of the Caspian Sea, changes in vegetation and soil
types, so the problem of glaciation affects all earth Sciences to varying degrees. The study of Quaternary glaciation, especially Holocene glaciation, is currently relevant for understanding climate change. Against the background of significant climate fluctuations within the epochs of glaciation, there are smaller cooling phases that cause the temporary onset of glaciers. Short-term climate fluctuations are manifested in oscillations – minor fluctuations in the languages of glaciers. All this indicates that the climate undergoes significant changes in a short time, which are reflected in the morphosculpture of the terrain, the latest deposits and modern precipitation. Glaciation of the Greater Caucasus in the Prikazbeksky region reached its maximum in the middle Pleistocene,when glaciers went far into the Ossetian basin. All these traces have been preserved due to the lower capacity of the Chanty-Argun glacier and its fluvioglacial flow, which developed during the late Pleistocene epoch. Volcanic activity, especially active in the late Pliocene and continuing up to the present time, is associated with the late horn stage of development of the Caucasus. The formation of the Rukhs-Dzuar molass formation more than 2 km thick in the late Pleistocene in the Ossetian basin of the Tersky-Caspian flexure is associated with the activity of volcanoes in the Kazbek volcanic region. In the early Pleistocene, volcanic activity on the BC decreased significantly. The most intense outbreak of volcanism in the Kazbek and Elbrus volcanic regions occurred at the beginning of the late Pleistocene, which roughly coincided with the maximum phase of the late Pleistocene (Bezengian) glaciation. Then, in the second half of the late Pleistocene, volcanic activity was manifested on the mount Kazbek. The last outbreak of volcanic activity occurred in the Holocene no more than 2-3 thousand years ago. Fresh lavas are available on Elbrus, Kazbek, in the Terek valley near villages. Sioni and on the Kel volcanic plateau. Fumarolic activity still continues on Elbrus. Thus, in the Kazbek region, eruptions occurred from the late Pliocene to the late Holocene inclusive.
ISSN 1998-4502 (Print) ISSN 2499-975Х (Online)