Consideration of multifactorial geomechanical-technological factors in determining the rational parameters for site outgassing technology at the Western Donbas mines (Ukraine)

Abstract The paper examines a promising component for the energy sector – development of gas reserves and gas production, taking into account the peculiarities of mining-geological and mining-technical conditions of the Western Donbas deposits (Ukraine). Two components of the solution to this issue are analyzed: the texture and physical-mechanical properties of weakly metamorphosed rocks and the use of high-performance complexes, reuse of extraction drifts with resource-saving technologies for their maintenance. Based on multivariate computational experiments, schemes have been developed to determine parameters for the location of outgassing wells. Three basic methodological provisions based on the conducted analytical research performed by the finite element method have been substantiated. Calculations, which are the basis for the methodology of selecting outgassing well location parameters, have been conducted. Experimental measurements conducted at six extraction sites of two mines confirm that the outgassing coefficient according to the recommended parameters exceeds that corresponding to the existing outgassing well location schemes in mines (the range of relative increase in the outgassing coefficient is from 19 % to 123 %). In addition, a significant influence (up to 35 – 60 %) has been revealed of the coal-overlaying formation texture, the well gradient angle (20 – 30 %), and the drilling step of outgassing wells (30 – 40 %). It has been found that an increase in the longwall face advance velocity improves the gas trapping efficiency by 25 – 40 %, leading to a decrease in the methane flow into adjacent mine workings and substantiates an opportunity to accelerate the longwall face advance.