Improvements in or relating to methods for the extraction of a subterranean mineral deposit using a fluid to dissolve or melt said deposit

摘要

844,229. Mineral-mining. FOOD MACHINERY & CHEMICAL CORPORATION. Aug. 6, 1958, No. 25221/58. Class 68(1). Mineral deposits that can be dissolved or melted by a fluid are mined by a method which involves sinking a shaft or shafts 10 to an interface between the deposit and the subjacent stratum 3, forcing fluid under pressure through the one or more than one of the shafts to the interface to form a fracture 32 along the interface to the bottom of a second pre-existing or subsequently formed shaft or shafts 15, and finally passing fluid from one shaft to the other by way of the fracture to dissolve or melt out the deposit. Pressure may be maintained on the fracture for some time after commencement of the removal of the deposit to prevent reclosing of the initial fracture. The shafts are preferably cased and the fracturing fluid may be passed down through such a casing 12 by a pipe 31 sealed in by a packer 30. The pipe 31 and packer 30 are withdrawn after the fracture has been made.