Forecast and prevention of coal and gas outbursts in the case of application of a new mining method - drilling of a coal pillar

Abstract

Coal and gas outbursts are one of risk factors accompanying the mining of coal in low seams in the Ostrava-Karviná Coalfield. At the use of the method of longwall mining, all coal reserves have not been mined out owing to tectonic faults. For mining out the residual reserves, the application of a new mining method - drilling of a coal pillar was proposed. The method of mining of a coal seam utilizing long large diameter boreholes is verified in the Paskov Mine (company OKD, JSC – Czech Republic) under conditions of rock mass with hazard of rock and gas outbursts in localities of residual pillars left in seams after finishing the mining operations performed with using the classical method of longwall working along the strike. [5] Forecast and preventive measures applied to the verification of the new method were based on previous experience with the mining of seams with hazard of coal and gas outbursts. They accepted fully valid legislation, i.e. Ordinance of Ostrava Regional Mining Authority No. 3895/2002 and supplementary materials (Instructions and Guidelines). The proposed measures respected the character of the method being verified. [4] For all areas being mined, projects containing also chapters specifying the problems of ensuring the safety of mining works and operation under conditions of hazard of coal and gas outbursts were prepared. In the contributions, basic proposals for the principles of coal and gas outburst forecast and prevention when applying the new mining method – drilling of a coal pillar are presented.