| 摘要 |
A method of mining in an unconsolidated structure is accomplished by forming a bore hole in the ground to at least the bottom of the structure to be mined, then casing the bore hole to a point at least five feet or less above the bottom of the bore hole. A sump is then formed between the bore hole and the bottom of the casing. A pump is positioned near the bottom of the sump, and a jet is positioned above the pump. Fluids are forced out of the jet against the formation while the jet is being moved vertically and axially in one direction about the axis of the bore hole to form an elongated slot in the formation. During the operation of the jet, the pump is removing dislodged formation material. After subsidence of the formation, the jet is continued in its rotation and vertical movement around the axis of the bore hole.
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