Experimental research on the haulage drifts stability in steeply dipping seams

Abstract

Purpose. Substantiation of the conditions for haulage drifts stability using different protection methods in steeply dipping seams based on a set of experimental studies. Methods. To achieve the purpose set, mine instrumental observations have been performed to study the rock pressure manifestations in zonal advance workings adjacent to the stope face on the haulage horizon. The conditions for their maintenance, within the mining site, are assessed by the side rocks convergence value on the drift contour and the change in the cross-sectional area, taking into account the deformation properties of the protective structures. Findings. It is recorded that in the zone of the stope works influence, in the most difficult conditions, haulage drifts are maintained, when coal pillars or clumps of prop stays are used for their protection. It has been determined that a decrease in the section of such mine workings up to 50% is the result of the protective structures destruction. When protecting the hau-lage drifts with the rolling-on chocks, a decrease in the mine working section up to 30% occurs in the process of the protective structures compression. It has been revealed that deformation of coal pillars or clumps of prop stays up to 10-20% leads to a loss of their stability, and an increase to 60% leads to a complete loss of their load-bearing capacity, intensification of rock displacements on the mine working contour and deterioration of its stability. It has been determined that in the process of deformation of the rolling-on chocks from sleepers by 20-60%, they are compressed without loss of load-bearing capacity, which ensures a smooth deflection of the overhanging stratum and restriction of rock displacements on the haulage drift contour. Originality. To study the deformation characteristics of protective structures above the drift, the function of the increment is used of side rock displacements on the haulage drift contour along the mining site length dependent on the relative deformations of protective structures, which makes it possible to assess the real dynamics of the process. Practical implications. When mining steep coal seams, using the specificity of geomechanical processes, which are manifested in an anisotropic coal-rock mass during unloading, satisfactory mine workings stability can be ensured by changing the deformation properties of protective structures above the drift.

Evaluation of the effectiveness of secondary support of haulage drifts based on a comparative analysis of the deformation characteristics of protective structures

“…To ensure the safety of site preparatory workings with pillar-free technological schemes for working out steep layers, it is proposed to use bushes made of wooden risers, which are installed intermittently above the sliding drift [7]. Being a mount of increasing support, riser bushes either break or are pressed into the lateral rocks, destroying them, as a result of which the arched mount in the drift is deformed.…”

“…The use of wooden risers to maintain lateral rocks above the drift allows one to limit the displacement of the roof and sole on the contour of the preparatory workings [7]. Meanwhile, in order to achieve the maximum effect of using this technique, it is necessary to increase the density of installation of risers, which is associated with additional costs of wood material.…”

Research on the Stability and Water Isolation of Waterproof Coal Pillars between Adjacent Working Faces under the Influence of Water Ponding Goaf—A Case Study

“…Additionally, it serves as a foundation for countries worldwide to formulate their diplomatic strategies. In China, the energy distribution pattern indicates that coal will continue to be the primary source of energy consumption in the foreseeable future [5][6][7][8][9]. Mine water surges caused by coal extraction are a significant challenge that affects the safe operation of mines [10,11].…”

Results of research on the stability of mine workings, fixed by arched supports made of composite materials, in the conditions of the Pokrovske Mine Administration

“…The arrangement and maintenance of the mined-out space are rather complicated process, especially in the conditions of deep horizons, where nonuniform rock pressure manifestations occur, which are typical for Pokrovske Mine Administration [9,10].…”