| 摘要 |
A method of mining a large underground seam of mineral, such as coal is described in which a first cylindrical shaft is drilled from the surface of the earth down to the mineral seam. A portion is enlarged at the base of the first shaft as a work room. A first radial shaft in the seam, out to a selected radius R, is drilled by conventional methods with the roofs supported by means such as hydraulic chocks which can be extended and moved selectively as the line of drilling progresses. When the first shaft is drilled, a continuous miner working on a short face method of mining is directly radially from the work room and is advanced outwardly until the width of the first radial shaft is such that the original wall of the first shaft has been cut away. The direction of the miner is then turned to be parallel to the first horizontal shaft and a short wall cutting advance is made to cut away the first wall of the first shaft and, in effect, drill a second shaft having a first wall spaced by the width of the cutter. A continuous flexible curtain is provided between the floor and roof, on the back side of the chocks, so that fresh air can be brought down through the vertical shaft and radially outward along the working face and back on the outside of the flexible curtain toward the working room and up to the surface in a second vertical or slope shaft. By widening the first shaft so that the second wall is at an angle to the first shaft, a circular area is cut out. If the second wall is parallel to the first wall, a rectangular area is cut out. Access to the work area can be from the surface, from a horizontal shaft or from an outcrop or in the case of an existing mine, access from shafts already available.
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