| 摘要 |
A hydraulic borehole mining system has a cutting jet nozzle supported on an insert short length of tubing of a cutting jet head within a water supply conduit in the lowest section of a multi-conduit pipe string that extends from the surface through a borehole to a target zone to be mined. A rod extending from the surface through the string outside of the water supply conduit connects to the head to reposition the nozzle vertically, independent of movement of the conduit or string. The borehole annulus is sealed and connected to a surface standpipe for development of a hydrostatic head pressure that acts, with or without downhole pump assistance, to raise the slurry created by the nozzle jet up through a second conduit in the pipe string. Material is pumped down the same second conduit after mining to backfill the hole.
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