Development of quick setting cement capsule for effective reinforcement in freshly exposed roof in underground coal mines

摘要

Roof control is a major problem affecting safety and productivity in underground mines. Roof falls itself account for nearly 44 percent of the underground fatal accidents. Freshly exposed roof, particularly in developing galleries are more prone to accidents. The supports being provided in the exposed roof are not effective to control the occurrence of falls. Now a days roof bolls are gaining immense popularity as they are economical and effective under Indian strata conditions. Full column conventional cement grouted bolts are generally giving an anchorage strength of 0.5 to 1,0 tonne in half hour after grouting. The above anchorage strength is not sufficient to hold the roof in the freshly exposed face. At present DGMS has made it compulsory to use such cement capsules which can provide minimum 3.01 anchorage strength after half an hour of installation. Central Mining Research Institute (CMRI) has developed a composition free from chloride which has given an anchorage strength of more than 3.0 tonne within half an hour after grouting. The composition was experimented on trial basis in Dhansar, Kusunda, Godhar and Putki Balihari collieries of Bharat Coking Coal Ltd (BCCL) and the technology has been released to Coal India Ltd (CIL) from CMRI.