Using the spatial structure of the external staggered split-level panel layout, a combined support technology for adjacent roadways was developed and analyzed for a rock bolt and anchor cable mechanism. The influence of the side rock bolt and anchor cable parameters on the mechanical properties of the anchorage body and the support stress distribution of the lateral coal body were revealed using the FLAC3D software. The optimal support parameters of the side rock bolts and anchor cables were subsequently determined, and the support effect of gob-side entry in a mining scenario was verified. The results show that the support of the side rock bolts and anchor cables improves the mechanical properties and stress state of the anchorage body, producing a good protective effect on the coal body of the air-intake entry roof and side wall. This is beneficial to the stability of the side wall and the realization of the suspension effect for roof rock bolts and anchor cables, which in turn makes the surrounding rock maintenance of the gob-side entry to a thick coal seam more favorable.

One of the ways to resolve the “green energy-economic development” dilemma, in which the coal industry is situated, is by the improvement of technologies and the integrated use of extracted resources, including methane gas as a clean energy source. Using the example of the Kirova mine, located in Kuznetsk coal basin—one of the ecologically unfavorable coal mining regions of Russia—this article discusses an integrated technology for the extraction of coalbed methane (ECBM), which makes it possible to reduce greenhouse gas (methane) emissions and improve the safety and intensity of coal mining. The Kirova mine, with its 3 Mt production in 2019, is one of the coal mining leaders in Russia. The available mining equipment has the potential to significantly increase the output; however, gas is a limiting factor to this. The customary approaches to coal seam degassing have already been petered out. The miners and mine science are facing a challenge to validate and test an alternative technology to ensure effective in-seam gas drainage prior to vigorous mining. This article gives an account of the improvement track record of the in-seam gas drainage technology used to pre-treat coal seams for intensive and safe extraction. This technology suggests, at the first stage, hydraulic loosening of the target coal seam through wells drilled from the surface (SSHL), then hydraulic fracturing (HF) of the coal seam through the boreholes drilled from underground development headings, followed by methane extraction from the high-permeability coal-gas reservoir created through standard in-seam gas drainage underground wells. Results are presented in this paper of field testing of the improved SSHL technique. Findings are presented on the effective parameters of the HF technology. Methodological recommendations are offered for selecting viable in-seam gas drainage technology.

Rock burst is one of the typical dynamic disasters in coal mining. In order to reveal the mechanism of rock burst from the energy view point, the relationships between the maximum, minimum, and intermediate principal stresses and the concentration coefficients of the gravity stress k1, k2, and k3 are determined through the geostress measurement combined with engineering practice of coal mining. The coal and rock system model based on the tectonic stress is established. The relationship between energy and scale radius of the coal and rock system is determined to reveal the law of energy accumulation, release, and transfer in the coal and rock system. In view of the characteristics of the porous medium in the coal seam, the measures of water injection are put forward to relieve pressure in the coal seam, and the law of water seepage in the process of water injection in the coal seam is studied based on the seepage mechanics. The result shows that the trend of released energy of damaged coal has good consistency with the variation of permeability, and water injection can reduce the stress concentration and energy concentration of the rock burst system. The engineering practice of the rock burst prevention was taken in Yuejin Coal Mine. The energy characteristics of the coal and rock system in the working face are analyzed, and the measures of water injection and the corresponding parameters are determined.

Despite advances in rockburst studies, suddenness of major geodynamic events is reported in a number of cases. Phenomenological tectonophysical model is suggested to explain some geodynamics phenomena. Prof. Petukhov I.M. suggested a concept: the Earth crust's critical stress condition is developed due to horizontal compressive forces and entrains rock strata from the sub-surface to a certain depth. The conditions that induced earthquake in 2013 at Bachat coal field in south west Kuzbass are considered in terms of critical stress developed in the top layer of the Earth crust. Estimates show that the size of the critical stress zone, produced presumably by interaction of huge (over 100 km) crustal blocks is at least 10km. Whereas critical stress zone is located in the top part of Earth's crust, mining operations in the pit including blast operations was making a direct impact on this area. Shallow occurrence of critical stress area and its size can provide insight into why mining works brought about induced earthquake with hypocenter at the depth of several kilometers. The conclusion has been made that regional areas of critical stress within rock massif developed as a result of crustal blocks interaction create hazard medium for mining.