METHOD OF UNDERGROUND METAL HEAP LEACHING FROM PERMAFROST ROCK Russian patent published in 2006 - IPC E21B43/28 

FIELD: mining industry, particularly for dissolving minerals other than hydrocarbons by an alkaline or acid leaching agent.

SUBSTANCE: method involves drilling injection wells and extraction well or extraction wells in deposit block to be developed; injecting working reagent solutions via the wells and extracting the production solutions; performing fracturing of productive horizon rock by blasting thereof in lower well parts to increase production horizon permeability; forming crushed and cracked zones in bottom rock in lower extraction well part for production solution accumulation, wherein the crashed and cracked zones are formed by rock blasting; injecting hot working reagent solution into the productive horizon. The working reagent solution includes additives, namely easy solving alkali or other metal salts having low eutectic temperature and not reacting with the working reagents and with possible intermediate products of reaction. The additives are mixed in amounts providing concentration near saturation.

EFFECT: possibility to create thawed working zone for following metal heap leaching in any season.