METHOD OF OPENCAST MINING OF FLAT DEPOSITS UNDER PERMAFROST CONDITIONS Russian patent published in 2003 - IPC

FIELD: mining industry; applicable in opencast mining of flat permafrost coal and placer deposits with internal dump formation. SUBSTANCE: method includes excavation of potentially fertile layer, block working of overburden bench, mineral extraction and transportation, alternating of filling of worked out space with formation of internal dump, using negative temperature of permafrost rock mass in cold season of the year, ice prism is frozen on, for instance, by sprinkling with help of GRAD device. In this case, volume of frozen-on prism is determined as difference of sum of volumes of minerals and overburden rocks in slope and volume of overburden rocks with consideration of loosening factor. To preserve ice prism in frozen state, heat insulating layer from overburden rocks is located above ice prism. Thickness of heat-insulating layer shall exceed depth of seasonal thawing in this region of permafrost zone. Technical result of method realization consists in filling of worked-out space with stripping factor below 1 and withdrawal of overburden rocks for other purposes, that provides for reclamation of opencast field. EFFECT: higher efficiency of method. 1 dwg