| 摘要 |
Apparatus for subterranean slurry drilling and mining of granular ore, such as phosphates, with a combined drilling and mining apparatus. The apparatus includes a tool string having a drilling head and mining head that are selectively interchangeable on its upper end for drilling into one or more ore strata to be mined and thereafter to remove ore from the strata as a slurry. The drill string includes a plurality of inner and outer pipe sections connected to a mining nozzle section, to an eductor pump section, and to a drill bit at its lower end. A drilling/mining liquid is directed through the tool string during both the drilling and mining modes of operation. During drilling, liquid is directed through a foot valve into the rotating bit to wash cuttings to the surface externally of the tool. During mining, the tool string is rotated, the foot valve is closed, and a mining nozzle is opened thereby causing liquid jetting from the mining nozzle to reduce the ore to a slurry. The slurry is pumped to the surface by liquid passing upwardly through the eductor pump and through the inner conduit. Without removing the apparatus from the hole, a hydraulic control system is actuated by hydraulic pressure equal to or less than system pressure for shifting the mining nozzle, the eductor nozzle, and the drill bit foot valve between a drilling mode and a mining mode thus enabling several different ore bearing strata to be mined.
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