METHOD FOR EXPLOSIVE DESTRUCTION OF FROZEN ROCK MASS Russian patent published in 2019 - IPC F42D3/04 F42D1/08 

FIELD: mining.

SUBSTANCE: invention relates to the field of drilling and blasting operations in massif of frozen rock mass in harsh climatic conditions. Method of explosive destruction includes the drilling of explosive wells, the formation in them of explosive charges with air cavities. At low temperatures, preparation for excavation of frozen rock mass is carried out in several stages. At the first stage, after drilling all the wells of the process unit according to the mining plan, it is divided into two parts and the part of the block to be excavated first, before the rock mass freezes, they are charged with a traditional relieving charge; in the rest of the block, in the lower third of the wells, a camouflet charge is formed and the whole block is blasting. After the explosion, the wellheads, blasted by the camouflet method, are covered with plugs to prevent it from shedding and frosting, for example, with polypropylene bags from ammonium nitrate. At the second stage, after the first part of the rock mass is removed, in the upper part of the camouflet-charged wells, a charge is formed with an air cushion of 15–30 diameters in length, for example, into a polypropylene sleeve, and the charged part of the block is blown up again. Second stage can be repeated several times, depending on the rate of freezing of the rock mass. After camouflet explosion, it is preferable to charge the upper part of the wells with granulites. Surface deceleration between charges is preferably from 30 ms/m.

EFFECT: invention makes it possible to increase the efficiency of blasting operations in open pit mining in cryolithic zone conditions.

3 cl, 3 dwg