The Calculation of Methane Concentration Emitted from the Coal Face

Abstract

The Paskov Mine belongs to the company OKD, a.s. with the production of hard coking coal from 1970. The applied mining method is the slabbing method in controlled caving, excavating the coal pillar by means of coal plough equipment loading mine run on rake conveyers and securing the excavation area with individual hydraulic or mechanical supports. The coal face is planned as one of the coal faces in continuous extraction of the seam by a shearer. Using the shearer at mines in the Paskov Mine is not a novelty. Shearer mining represents some problems. Besides the hazard of methane-air ignition, there is a mixture of coal dust – methane – air, which is more dangerous even in the case of lower concentrations of dust and methane than their individual lower limits of explosiveness. A decision was made then that shearers would gradually be replaced with coal ploughs in all coal faces. The article contains the calculation of the volume of methane emitted as a result of excavation, determining methane concentration during excavation, lowering the hazard of methane layers being formed, and finally evaluating the suitability of the proposed system of the coal face ventilation.