METHOD OF PREPARING COAL SEAMS FOR EXTRACTION Russian patent published in 2001 - IPC

FIELD: mining. SUBSTANCE: method includes driving of mine workings, sinking of seam boreholes, their sealing, injection into seam through boreholes of working fluid under static regime, hydraulic pulse treatment of seam, connection of boreholes to degassing pipeline and softening of seam just before beginning of stoping. In driving of initial working, downholes are sunk beyond the contours of anticipated workings up to their connection to degassing pipeline and working fluid in the form of energy liberating system is injected which is initiated after filing of fractures. Then horizontal degassing boreholes are drilled round anticipated workings and hydraulic pulse treatment of rock mass is effected through additional boreholes drilled in acting stoping field. Energy liberating system is used in the form of mixture of ammonium nitrate, water and glycerin. Said system is initiated at fluid pressure of at least 12 MPa. EFFECT: higher safety of development and stoping operations. 3 cl, 10 dwg