When compared internationally, German coal deposits are at a greater depth and have a high degree of penetration with a comparatively lower ancillary strata stability. This produces a high stress-strength ratio, which places high demands on the rock bolting technology when driving the gateroads. To permit the technical and economically successful use of rock bolts under these marginal conditions, rock bolting technology was further developed during the 90's in German coal mines, and adapted to the deposit conditions. For conditions where the sole use of system bolts cannot be employed, support combinations of rock bolts and standing supports were developed in various configurations. In conjunction with the increased use of retreat working, rock bolting technology will in future become an essential module for high-performance longwall operations in German coal mining.
展开▼
