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Abstract

Evaporite mineral solution mining process and apparatus comprising the steps of undercutting a bed or massive deposit by in-air jetting with an aqueous solution followed by solution mining of the mineral above the undercut with monitoring and control to cease the solution mining when the roof rock is adequately exposed to maintain a stable roof and stable pillar support. The resulting cavity exhibits steeply angled, nearly vertical sidewalls, flared upwardly and outwardly only 10° to 15° from the vertical plane normal to the edges of the undercut as compared to 45° typical for morning glory cavities. A first plan vertical production well is drilled with a sump provided substantially adjacent to the floor rock. A second horizontal well is developed up dip to intersect and communicate with the production well. The air jet tool mechanism provides horizontal, slightly upwardly inclined jets (0°-15°) which cut the mineral laterally on both sides of the tool which is gradually withdrawn up dip as the undercut progresses. The tool also includes and EMR ranging system, preferably a radar system, and a MWD unit to transmit data to the surface. This permits undercut width control to develop a substantially rectangular undercut profile. The subsequent controlled solution mining provides a substantially rectangular room throughout the entire horizontal length which provides improved mineral recovery, steeply angled pillar wall profiles controlled roof span and increased dissolution rate. The method and apparatus is applicable to beds having dips from 0°-90° and multiple beds with or without partings.

Other References

• "Solution Mining of Halite Through Boreholes" Charles Jacoby SME Mining Engineering Handbook vol. 2, 1973 pp. 21-49 thru 21-5