METHOD FOR DEVELOPING THAWED PLACERS Russian patent published in 2021 - IPC E21C41/22 

FIELD: mining industry.

SUBSTANCE: invention relates to the mining industry, it is created primarily for the development of placer deposits or their sections located in thawed zones. A method for developing thawed placer deposits includes opening with inclined shafts, breaking sand with well fans into the clamping medium, end release of broken sand and delivery of broken rock mass to the surface. The method is characterized in that along border 5 of placer deposits, along the strike, below the deposit soil, field pumping drift 6 is laid, located in stable rocks, from which, transversely to the placer strike along native rocks of raft 3, drill haulage drifts 10 are laid to the opposite edge of the placer, placing their roof below the deposit soil by the value m, equal to the depth of the metal subsidence in the placer raft. At the end of each drill haulage drift 6, a cut-off riser is passed to the roof of productive reservoir 1, after which a cut-off gap is formed by blasting wells on the cut-off riser, on which the sand is broken in the conditions of the clamping medium in the retreating order by blasting 2-5 fans of boreholes drilled from drill haulage drifts 6 to the roof of the reservoir. The angle of inclination of the extreme boreholes in the fan is 45-50°, while the distance between the sides of adjacent drill haulage drifts 6 are defined as 2m.

EFFECT: use of the present invention will increase the extraction of metal from the subsoil due to the sub-working of the raft and ensure high labor productivity during the development of thawed placer deposits by improving the level of work mechanization in the result of the location of underground mine workings in the stable rocks of the raft and the possibility of using high-performance self-propelled equipment.

1 cl, 3 dwg