METHOD FOR INCREASING OF PERMEABILITY OF PAYABLE SEAMS Russian patent published in 1996 - IPC

FIELD: mining industry; applicable in degassing of gas-bearing coal seams. SUBSTANCE: method for increasing of permeability of payable seams includes determination of rock density by geophysical method. Then, vertical slot is cut with the aid of sand-jet perforation, and rock density on the slot section is determined. Then, drill pipe-borehole annulus is closed, and working fluid with sand is injected to built up maximum permissible pressure in the annulus. Micro- and macrocracks are wedged and secured through a distance 2-3 times larger than the depth of the crack itself. The annulus is opened and slot is repeatedly cut in rocks of payable seam. Creation of the second main relieving slot in the high stress zone allows utilization of rock pressure in slot cutting to increase the width and depth of the slot and to extend the zone of relief. EFFECT: higher efficiency of the process after formation of relieving slots. 2 cl