Analysis of applying blast-free technologies in conditions of cryolithic zones

Abstract

Operation of mining equipment has been analyzed at coal, diamond mining and other min-ing enterprises in conditions of cryolithic zones. Hydraulic breakers, dynamic buckets on ex-cavators, rippers on bulldozers, bar cutters, continuous mining machines, and in some cases, rotary mechanical shovel are used in blast-free mining. It is noted that the hydraulic shovels are characterized with high excavation forces, can be used in selective mining, can clean the foot wall without using a bulldozer, and can reduce or sometimes completely eliminate drill-ing and blasting operations. Boundary values of the face slope angle depending on the ambi-ent temperatures were established during the tests of RS-5500 at the Neryungrinsky open pit mine. Its value is equal to 46º in positive temperature; while during the interseasonal pe-riods the value stands at 60º, and in conditions of extremely low temperatures this value reaches 72º. Experience of using the LIEBHERR hydraulic shovels in building stone quarries shows that the uniaxial compressive strength of the rocks developed without blast pre-conditioning can reach 20-150 MPa. The Caterpillar company proposed a technology for ripping and excavating rocks (up to hard rocks) with quickly replaceable attachment tools. Based on analyzing physical and mechanical properties of the overburden rocks and coal at the deposit with account of cutting forces of the working tool, Mining Institute of the North of Siberian Branch of the Russian Academy of Sciences justified the possibility of using and es-tablished estimated performance parameters of the KCM-2000P Continuous Miner for the rocks and coals of the Elga deposit. Taking into account mining and geological conditions and rock properties of the Elga deposit, specialists of Wirtgen International GmbH calculated the technical and economic parameters of coal and overburden excavation using the Wirtgen 4200SM Surface Miners with loading into the 130-ton dump trucks.