METHOD FOR MINERAL PREPARATION ALONG WITH RELEASING THEREOF FROM UNDER-ROOF LAYER Russian patent published in 2006 - IPC E21C41/16 

FIELD: mining industry, particularly methods of underground mining.

SUBSTANCE: method involves advancing breakage face in under-roof layer; drilling bores in the under-roof layer and injecting weakening reagent to separate zones through the bores; drilling blind drift in front of the breakage face, wherein the blind drift has length of not less than breakage face length; drilling bores for following weakening reagent injection from the blind bore; additionally boring intermediate bores between above bores for following gas exhausting; performing under-roof layer development so that non-developed bank is left directly above breakage face support; performing stepwise weakening reagent injection into corresponding bores and evacuating gas from intermediate bores; leaving bores filled with weakening reagent for 1-2 days and supplying the weakening reagent into intermediate bores.

EFFECT: increased efficiency of mineral preparation.

3 cl, 3 dwg