Mine coal seam hydromechanical extraction - involves jet nozzles following up point of attack as extraction progresses

摘要

A seam of coal between two extraction sites is extracted disc-wise in a reverse process, with a high-pressure water jet from one or more nozzles undercutting the disc, which is then recovered hydromechanically, in a mine. In the course of hydromechanical engagement, the nozzles (44) are guided along behind the point of attack, in accordance with the progress of extraction. The break-in may be driven forward so that the face of the disc is inclined steeply backwards towards another extraction site. A main jet may be swivelled in one or more planes. Hydromechanical attack is made independent of the weakening and widening jet, as distance increases.