APPLICATION STUDY ON COOPERATIVE DRAINAGE TECHNOLOGY FOR MINING-AFFECTED PRESSURE RELIEF GAS IN OVERLAYING ADJACENT SEAMS

Abstract

Yangquan mine area, one of the most difficult gas drainage mining area in China, has multiple coal seams and high gas emission [1]. Statistical analysis of gas sources in pairs of mine showed that the adjacent seams were the main sources of gas emission of mining faces, and whether this part of gas could be appropriately controlled would influence the safety production status of the faces and mine. Take mined faces of 12# coal seam in Nanzhuang mine for example, many years’ on-site observations showed that the main gas sources of mining face of 12# coal seam were 12# coal seam, overlaying adjacent seams and lower adjacent seams. Calculation results indicated that the gas quantity emitting from the overlaying adjacent seams, which was the focus of drainage, accounted more than 85% gas emission of mining faces of 12# coal seam. For the purpose of draining this part of gas, high-located boreholes were arranged in tail roadway, which took a good drainage effect on the gas emitting from 8# and 9# coal seams, but the gas emitting from 11# coal seam and other overlaying adjacent seams which were closer to 12# coal seam was ineffectively controlled. This part of gas, which had a fast emitting speed and large quantity, often caused gas concentration exceeding limitation. In order to reverse this trend, measures like increasing air volume and limiting the production had been carried out. In such a case, however, not only the production efficiency was reduced, but the safety exploitation was constrained severely. Thus, new technologies for controlling the gas emitting from overlaying adjacent seams of 12# coal seam must be studied on.