PROCEDURE FOR WEAKENING MARGINAL MASSIF OF MINE WORKINGS AT DEVELOPMENT OF COAL BEDS Russian patent published in 2010 - IPC E21C41/18 

FIELD: mining.

SUBSTANCE: invention refers to mining, particularly to development of coal beds with hard-to cave roofs and can be implemented for weakening marginal massif of mine workings at coupled preparation of extraction pillar. The procedure consists in drilling a system of relief holes in front of a breakage face beyond an abutment zone from a conveyor way to a zone of concentration of tensile stresses in plane of natural angle of cave, and in forming initial fissures by means of depositing and exploding a cumulative charge of explosive substance (ES) in each borehole, cumulative excavation of which is oriented along axis of the conveyor way. Further the procedure consists in sealing boreholes and in pressurising fluid into them under the mode of hydro-break of main roof rock. Upon drilling couples of approaching boreholes and boreholes above a coal massif at the next weakened section and simultaneously with formation of initial fissures in the relief boreholes of the first system oriented along axis of the conveyor way there are formed initial fissures by means of depositing and exploding cumulative charges of ES in the relief boreholes of the second system, cumulative excavations of which are directed to the main system of fissures of main roof rock.

EFFECT: facilitating operational condition of coupled workings at moment of main roof squeeze and correspondingly safe conditions of extraction pillars preparation.

2 cl, 9 dwg