METHOD FOR LOOSENING FROZEN ROCK Russian patent published in 1999 - IPC

FIELD: construction engineering. SUBSTANCE: method relates to artificial thawing of frozen rock in mining industry and construction activities and it can be used in underground development of placer deposits. According to method, after creation of ice-filled fracture resulted from hydraulic fracturing, delivered between at least two wells is salt solution of saturated concentration so that discharge from other well contains solution which is impoverished down to concentration corresponding to non-freezing of solution at initial temperature of frozen rock. After that, connected to central metal pipes through which solution is delivered is industrial electric power to perform electric thawing operation. On completion of thawing operation, initiated again is procedure of injecting concentrated solution so as to obtain at outlet from other well such solution which is impoverished down to concentration which corresponds to its non-freezing at initial temperature of frozen rock. To prevent contact between solution contained in pores of thawed loose rock and frozen rock of roof of productive bed, in completing stage of work air is injected under pressure through one of wells until stopping outflowing of solution from open central pipes adjacent to one or several wells. In application of aforesaid method, due to electric thawing of rock along horizontally oriented layer with maintaining preset concentration of solution, reduced are labour-inputs. This is achieved due to exclusion of operation for draining filtration flow. Also ensured is uniform selective loosening of productive bed, thus allowing for using mechanized extraction facilities instead of drill-and-blast procedure resulting in reduction of overall production cost. EFFECT: higher efficiency. 1 dwg