METHOD FOR DEVELOPMENT OF THICK STEEP-DIPPING COAL SEAMS Russian patent published in 1999 - IPC

FIELD: mining industry. SUBSTANCE: method is intended for underground development of thick steep-dipping coal seams. According to method, extraction of coal is effected in blocks. Drilled in blocks are deep bore-holes and they are blasted by one event with millisecond delay. Amount of extraction in block depending on thickness of coal seam is taken as equal to 5-10% of block volume. Driven from rising openings are horizontal and/or inclined openings which go across strike. Drilled from them are horizontal and low-inclined bore-holes in strike. After blasting of bore-hole charges, process of coal release from block is carried out at crushing of weakened coal mass in self-caving mode. So as to use ventilation and sublevel drifts to maximal degree in function of compensation space and to increase degree of coal mass weakening, bore-holes drilled from single opening are blasted simultaneously. Blasted at first step are bore-holes in upper and lower drill openings with similar millisecond delay. After that, blasted are bore-holes driven from other drill openings at direction of delay towards center of block. For more efficient process of self-caving, destruction of coal mass in lower part of block is performed by blast-hole charges fired in one stage with blast-holes overcoming them by series with millisecond delay between series. Aforesaid method allows for reducing labour-intensity and cost for preparation and working of coal block by 50%. This is achieved due to reduced scale of driven development openings, improved quality of drilling around coal mass, reduced expenses for drilling and charging of bore-holes, improved quality of weakening and crushing of coal mass, improving intensity of coal release and correspondingly increasing productivity. EFFECT: higher efficiency. 2 cl, 3 dwg