초록 ▼

Disclosed is a method of preferentially solution mining potassium chloride from a stratified subterranean deposit of potassium chloride and sodium chloride where a plurality of strata are present in a single common solution mining cavity. According to an embodiment of the disclosed method, a first a

Disclosed is a method of preferentially solution mining potassium chloride from a stratified subterranean deposit of potassium chloride and sodium chloride where a plurality of strata are present in a single common solution mining cavity. According to an embodiment of the disclosed method, a first aqueous working solution is established in a lower zone of the cavity in contact with lower strata. Thereafter, a second aqueous working solution is established in contact with a higher zone intended to be preferentially mined. The second aqueous working solution is maintained at a lower specific gravity than the first aqueous working solution. Effluent is withdrawn from the second aqueous working solution near the lower boundary thereof and an extracting solution is added to the cavity at a rate sufficient to maintain the second aqueous working solution less dense than the subjacent solution, i.e., the first aqueous working solution. The disclosed method is useful in preferentially mining zones that have a potassium chloride content substantially different than adjacent zones.

대표청구항 ▼

In a method of solution mining chloride salt from a stratified subterranean deposit of at least two chloride salts wherein the ratio of the chloride salts to each other varies between strata within the deposit which method comprises establishing a solution mining cavity in said deposit, feeding aque

In a method of solution mining chloride salt from a stratified subterranean deposit of at least two chloride salts wherein the ratio of the chloride salts to each other varies between strata within the deposit which method comprises establishing a solution mining cavity in said deposit, feeding aqueous solvent into the solution mining cavity thereby dissolving chloride salts from the deposit to form a first aqueous working solution within the cavity, mining upwardly through said deposit, and withdrawing first working solution as an aqueous effluent from the cavity, the improvement comprising: feeding aqueous solvent into said cavity and withdrawing first aqueous working solution effluent from said cavity until a preferentially minable higher zone having a different ratio of chloride salts than the layer subjacent thereto is reached; injecting aqueous solvent having a density less than the density of said first aqueous working solution into the cavity above the surface of said aqueous working solution and above the bottom of the zone being preferentially mined; dissolving chloride salts from the higher zone into said less dense aqueous solvent whereby to establish a layer of a second aqueous working solution; and withdrawing effluent from the second aqueous working solution within said cavity near the bottom of the zone being preferentially mined, while maintaining said second aqueous working solution less dense than said first aqueous working solution and substantially undiluted by said first aqueous working solution, said effluent having a higher salt content than said less dense aqueous solvent.