| 摘要 |
<p>A method of mining thick seam materials is performed by forming a pair of generally horizontal, vertically spaced, vertically aligned passes or drifts in one side of the thick seam. A number of contiguous vertical holes are drilled in the material from the lower to the upper drift to form a relatively large opening extending the length of the drifts. This large opening is then filled with low grade concrete to support the overburden and, after the concrete is set, a second pair of generally horizontal, vertically spaced, vertically aligned drifts are formed adjacent to the first mentioned drifts and the foregoing process is repeated. The above steps are continued until the entire seam of material has been removed. Each individual hole between an upper drift and a lower drift is formed by first drilling a relatively small diameter hole from the upper drift to the lower drift, following which a relatively large diameter reamer bit is then coupled to the drill shaft and the drill shaft is raised and rotated to cause the reamer bit to mine the materials from the bottom drift to the top drift, the materials falling into the lower drift and being removed in any suitable manner.</p> |
