GB1209643A - Solution mining - Google Patents

Abstract

1,209,643. Solution mining. KALIUM CHEMICALS Ltd. 10 Nov., 1967, No. 51165/67. Addition to 1,117,995. Heading E1F. A modification of the method, as described in parent Specification for providing an extraction surface to allow of solution mining of a stratum of product material located above an existing cavity by forming a fracture between two boreholes at an interface between the product stratum and an adjacent stratum of dissimilar material by introducing to said interface fluid at a pressure in excess of the normal hydrostatic pressure at the interface but considerably below the pressure normally required to fracture a similar product stratum at the depth of the interface to induce a fissure along the interface when no cavity exists beneath the product stratum. The modification is that now the fracturing fluid is supplied through one of a number of conduits located in a borehole to fracture the interface around the borehole to allow of solvent to be subsequently passed through the fluid-supplying pipe to the interface and then to be withdrawn after dissolving soluble material from the product stratum up another pipe in the borehole. Preferably this method involves the use of a tubular conduit 22 disposed concentrically within a casing 21 for the borehole, said casing being apertured at 24 in the vicinity of the interface above and below a plug 26 sealing off the space between the conduit and the casing.