METHOD FOR DEGASSING OF COAL SEAMS Russian patent published in 1999 - IPC

FIELD: mining industry. SUBSTANCE: according to method, bore-holes are drilled from ground surface in direction of coal seam being worked with subsequent connecting these bore-holes to vacuum pumping station for extracting gases from coal seam. In process of drilling, assessed is strength of drilled layers of rock matter so as to separate strongest layer with exceeding arithmetic mean value of all other layers by at least 10%. This layer must be located at minimal distance from coal seam being worked. Thickness of selected layer must be not less than 0.1 a, where a - width of longwall in coal seam being worked. Bore-hole is drilled down to floor of this strong layer which is considered as gas-screening. Upper part of bore-hole is cased to corresponding depth which depends on descending angle of coal seam being worked, distance from axis of longwall of edges of next column, and also on angles of fracture on ascending, descending or extension selected with respect to orientation of longwall being worked. Application of aforesaid method gives higher efficiency in degassing due to long period of operating degassing bore-holes and reduced cost of preparatory activities. EFFECT: higher efficiency. 1 cl, 1 dwg