| 摘要 |
<p>BORE HOLE MINING Minerals, in particular coal, that have been deposited in layers or along seams in the earth can be mined utilizing large diameter bore hole drilling equipment. With the drilling equipment stationed on the surface of the earth, a drilling member is drilled down into the earth along the seam of the mineral deposit. If the mineral deposit extends at an angle to the earth, i.e. less than 90.degree., the drilling operation is conducted so as to drill at a similar angle to the earth. As the mineral deposits are broken up during the drilling operation, the broken fragments are removed from the drilled hole. After drilling has occured for a certain distance in a forward direction, a creeping effect is induced in portions of the side walls of the drilled hole. The drilling member is then retracted from the drilled hole in such a manner so as to drill out any mineral fragments in the hole of the drilling member. These mineral fragments are then removed from the hole as the drilling member is retracted. The removal of the mineral fragments can best be accomplished utilizing an hydraulic flow mechanism for circulating fluid through the drilling member and removing the mineral fragments as they are drilled.</p> |
