On the example of the Alardinskaya mine, the problem of underground mining of seams prone to spontaneous combustion and rock bumps in the conditions of the Kondomsky geological and economic region of the Kuznetsk coal basin is considered. The contradictions in the requirements of regulatory documents for the width of the inter-panel coal pillars in the mining of seams with longwalls in conditions of endogenous fire hazard and in the mining of seams that are dangerous due to geodynamical phenomena are discussed. These contradictions impede the safe mining of seams using traditionally used layouts with the danger of spontaneous combustion of coal and rock bumps. A mining-geomechanical model is presented, which is used for numerical three-dimensional simulation of the stress-strain state of a rock mass with various layouts for longwall panels using the finite element method. The results of the numerical analysis of the stress state of the rock mass immediately before the rock bump are presented, and the main factors that contributed to its occurrence during the mining of the seam are established. A dangerous degree of stress concentration in the coal seam near the leading diagonal entries is shown, especially in conditions of application of abutment pressure from the edge of panels’ gob. The analysis of the features of stress distribution in the inter-panel pillar at different widths is carried out. Recommendations for improving the layout for the development and mining of coal seams that are prone to spontaneous combustion and dangerous in terms of rock bumps in the conditions of Alardiskaya mine have been developed. The need for further studies of the influence of pillars for various purposes, formed during the mining of adjacent seams, on the stress-strain state of previously overmined and undermined seams is shown.
The reasons for the lag of the indicators of the leading Russian coal mines engaged in the longwall mining of the flat-lying coal seams from similar foreign mines are considered. The analysis of the efficiency of the longwall face move operations at the JSC SUEK-Kuzbass mines was carried out. A significant excess of the planned deadlines for the longwall face move during the thick flat-lying seams mining, the reasons for the low efficiency of disassembling operations and the main directions for improving the technology of disassembling operations are revealed. The directions of ensuring the operational condition of the recovery room formed by the longwall face are considered. The recommended scheme of converged coal seams mining and a three-dimensional model of a rock mass to justify its parameters are presented. Numerical studies using the finite element method are performed. The results of modeling the stress-strain state of a rock mass in the vicinity of a recovery room formed under conditions of increased stresses from the boundary part of a previously mined overlying seam are shown. The main factors determining the possibility of ensuring the operational condition of the recovery rooms are established. It is shown that it is necessary to take into account the influence of the increased stresses zone when choosing timbering standards and organizing disassembling operations at a interbed thickness of 60 m or less. A sufficient distance from the gob of above- or undermined seams was determined to ensure the operational condition of the recovery room of 50 m, for the set-up room – 30 m. Recommendations are given for improving technology and organization of the longwall face move operations at the mines applied longwall mining of flat-lying coal seams with the formation of a recovery room by the longwall face.
The analysis of a current state of a problem of effective and safe working off of stocks in complexity mining-and-geological parameters is made. Recommendations about ensuring increase of technical and economic indicators of the coal mines which working off high-gas-bearing layers and spontaneous-combustion coal are made.
The results of the aero- and gas-dynamics processes numerical researches for the sublevel caving mining system with mechanized roof support in conditions of «Kiselevskaya» coal mine are given in the article. It is shown, that reliable and effective panel ventilation is provided with the technological scheme with three entries at the each sublevel. The parameters of the technological scheme are determined.
The security issues of the deep mining of Prokopevsk-Kisilevsky deposit the Kuzbass are considered. The analysis of the existing technologies and systems development are executed. The recommendations to improvement of the technical and economic parameters, reducing accidents and injuries of the working off inventories powerful coal steeply inclined seams and steep coal seams were given.
The analysis of a current state of a problem of emergence of endogenous fires is made at working off of coal layers in mines. Influence of mining-and-geological conditions on efficiency and safety of working off of the layers inclined to selfignition is considered. Need of an integrated approach to a solution of the problem of endogenous fires is shown at working off of stocks in difficult mining-and-geological conditions.
The questions of an assessment of production potential are considered here.The defining role of resource potential is given at an assessment of production capacity of mine. Recommendations for determination of rational capacity of mines are given. The necessity of strategic innovative development of coal-mining enterprises is shown.
Existing techniques of an estimation of degree of complexity of mining-and-geological parameters for the forecast of efficiency of economic investments at development of new coal-fields are analyzed. The scheme of typification of stocks on complexity of mining-and-geological parameters both economic efficiency of working off and the technique of grouping of deposits and their sites are offered.
The complex method of a substantiation of ways maintenan to stability of local development excavations in overworked layers is offered. The mark of expected displacement of breeds contour of section local preparatory developments overworked layers is executed. Recommendations about realization overworked systems of working out in the conditions of mine «Raspadsky-koksovaja» are made. Necessity carrying out of developments of 2nd layer with backlog from a clearing face of 1st layer is proved. The mark of influence of parameters of an applied way maintenan to stability of developments on level of production costs is executed.
The analysis of the modern state and perspectives of development of underground coal mining in Kuznetsky coal basin has been carried out. Problems of underground mining of coal seams have been determined. The factors which significantly effect the efficiency of coal mines have been reviewed. The conclusion on necessity of improvement of mining methods for coal seams in complex geological conditions have been made.
Challenges of efficient underground mining of thick flat coal seams are studied. An effective method to secure stability of site development workings in overworked layers is suggested. A conclusion is made on advisability of stress-relief workings construction in preparation of overworked layers. Parameters of slicing mining system and stress-relief workings are justified. Assessment of useful mineral loss enhancement and production cost reduction is made due to introduction of the proposed method. Possible areas are determined for application of this method.
The pipeline from two hinge the sites located along a face, and two telescopic sites on lines is synthesised. Influence of a design of the hinge on losses of pressure and the central corner divergence of hinge sections on effort of its reduction is analysed. The diagramme of communication of width dredging strips of coal with capacity of a layer is offered at the set level of losses of pressure of water in hinge the pipeline and effort of its reduction.
Analysis of perspective flow diagrams of layered mining of high flat coal-seam in the Kuzbass Region is carried out. A conclusion in made on the necessity to consider the influence of the underworked massif of the 2nd layer in determination of the ultimate thickness of the interlayer coal pack. Analytical studies of the stress-and-strain state of the underworked massif have been made. Sizes of weakened coal zones are determined and recommendations are given how to determine the ultimate thickness of the protective pack.
The know-how of layer improvement of thick hollow seams in the mines of Kuzbass is analyzed. The conclusion is made about the necessity of subcladding justification of the location of local development workings of layer 2, providing the minimization of costs for their development and maintenance. The influence of mining engineering factors on the stress-strain state of rock massif in the vicinity of layer 2 layer workings has been investigated. Recommendations on the choice of rational location of local development workings are made. The economic benefit from the implementation of the developed recommendations is estimated.
The article analyzes the impact of endogenous fire hazard of the development of strata prone to spontaneous combustion, in particular, with the use of modern efficient equipment, on the technical and economic performance of the mine. The conclusion is made about the necessity of differentiated approach in the choice of technology for the development of mined seams. The effective technological scheme of development of strata prone to spontaneous combustion is proposed. The influence of the first layer development on the stress-strain state of the underlying layers is investigated and rational parameters of technological schemes are determined. The economic effect from the introduction of the developed technology is calculated, which is obtained by reducing the number of endogenous fires and minimizing the damage in case of their occurrence.
The paper analyzes the results of mine observations on the condition of area preparatory workings during layer mining of thick gentle strata of Kuzbass. The conclusion is made about the necessity of additional justification of the location of area preparatory workings of the 2nd layer, providing the reduction of costs for their maintenance. The stress-strain state of the rock massif (STS) "perturbed" by the 1st layer mining was investigated. The nature and degree of influence of the 2nd layer overmining were established. The rational location of the 2nd layer preparatory mine workings was chosen for the sloping mining of layer III of the Tom-Usinsky region of Kuzbass. The economic effect from the implementation of the developed recommendations is calculated, which is obtained by reducing the cost of maintaining the operational condition of the area excavations.
The factors that have the greatest impact on the probability of occurrence of endogenous fires in the mining of powerful steep seams of the Prokopyevsko-Kiselevskoye field of Kuzbass have been established. The differentiation of endogenous fires by reservoirs in the conditions of Prokopyevskugol Management Company LLC was carried out. The influence of the main mining and technical factors on the probability of spontaneous ignition of strata was studied. It was concluded that during the mining of thick steep seams, the main cause of spontaneous ignition is the abandonment of interstory coal pillars, which are concentrated accumulations of destroyed coal. The principles of designing technological schemes for mining seams prone to spontaneous ignition are formulated. A method of mining powerful steep seams prone to spontaneous ignition that excludes leaving inter-story coal pillars and ensures reliable isolation of the mined area is proposed.
The structure of mineral resource losses during mining of thick steep-sloped and steep seams with the use of the system of under-stage hydraulic extraction in the conditions of OAO Prokopyevskugol was determined. The influence of the main mining-geological and mining-technical factors on losses of minerals was studied. The factors that have the greatest influence on the mineral extraction coefficient were determined. It is concluded that, when determining the height of the subfloor, it is necessary to consider the width of the squeeze zone formed at the border with the mined-out space. The method of determining the parameters of the squeezing zone in the area of the influence of the mining operations is developed. The principles of designing the technological schemes of the mine workings are formulated. Recommendations on the rational arrangement of sub-stage drifts in different mining and geological conditions were developed. The economic effect from the implementation of the developed recommendations was calculated.
An analysis of the causes of accidents associated with dynamic collapses of the roof rocks in the development system with sub-stage hydraulic extraction in the mines of OAO Prokopievskugol has been carried out. The hypothesis about the mechanism of dangerous dynamic collapses of coal and roof rocks is put forward. It is concluded that, when determining the height of the subfloor, it is necessary to take into account the width of the pushback zone formed at the boundary of the clearing works. The influence of the main geological and mining-technical factors on the parameters of the squeezing zone was studied. It has been proven that the following factors have the greatest influence on the width of the squeezing zone: the depth of the mining works, the thickness of the mined seam, the strength of the coal. Recommendations for determining the height of the subfloor, providing safe working conditions for miners in the conditions of the hydro mine Tyrganskaya are developed. The method of mining subfloors with an increased height is proposed. For its implementation the size of the squeezing zone and the length of the working jet of the hydraulic gun is calculated and the position of the undestroyed coal zone is determined taking into account these parameters. Coal massif de-strengthening in this zone is made to exclude the coal pack hang-up by, for example, hydraulic fracturing or explosion of explosive charges. The economic effect of implementing the developed recommendations has been calculated.
In modern market conditions, the viability of coal mines is determined by the competitiveness of their products. In turn, the competitiveness of mined coal depends on production costs. The solution of the problem of production costs reduction is vital for practically all Russian mines. The most acute problem of decreasing costs is for mines developing powerful steep seams of Prokopyevsk coal deposit in Kuznetsk coal field, where there are big coal reserves, and mining and geological conditions don't allow to use high-capacity cleaning equipment. Objective prerequisites for a sharp reduction of production costs in the mining of powerful steep seams are created by the hydraulic technology of coal mining. The purpose of this work is to create patentable, cost-effective technological schemes to reduce the amount of cutting work, reduce losses and improve the safety of miners. The idea of the work is to increase the height of the substage due to advanced loosening of the coal in its upper part. As a result of this research, a method of excavation of thick steep seams was developed, which allows: to reduce the cost of cutting work (40-50%), to exclude dynamic phenomena such as an air wave with a high velocity pressure, associated with simultaneous collapse of the roof rocks in large areas.
