Investigation of factors affecting floor heave and convergence of galleries in Tabas coal mine

In Tabas coal mine (Parvade 5), the heave and convergence are ever known subjects of the ground control problems that have caused significant deficiencies particularly in the reuse of tailgates. The abutment pressure, the horizontal stress, the ground water, the exploitation method and the nature of layers in roof and floor of coal strata could be considered as the most effective factors in floor heave and sidewalls convergence in galleries. Detailed investigations in Tabas coal mine (Parvade 5) showed that the abutment pressures are major factors for increasing the length of packs and their reinforcing in downside of the stop along with the usage of rib pillar and pack in upside of the stop in addition to the blasting of roof in gob zone have been selected here to overcome the problem. Applying these techniques resulted in the reduction of the intensity of floor heave and sidewall convergence. Thus deformation of height and width has reduced 64.58% and 40%, respectively.