Roof layer underpinning in walking coal mine working - involves reinforced concrete filling in deep slit in adjacent rock

摘要

The system is used in transitional areas in underground mining on seam-type mineral deposits esp. coal for intercepting roof layers and securing gallery edges. A slit (6) of greater depth (b) and height (a) is made in the adjacent rock (9), parallel to its plane, in the lengthways area of the gallery (1) above the seam (5). The slit filled with reinforced concrete (7), forming a continuous load bearing strip (8). It enables roof layers to be directly underpinned along the whole area, in the course of striding working. This is secure and widely applicable.