Deployment of Continuous Miner in Under Ground Coal Mine – A Case Study of Sarpi Mine.

The continuous miner technology (CMT) is being adopted extensively in underground coal mines of India as Mass Production Technology (MPT). This technology potentially eliminates the two-unit operating, namely the drilling and blasting. This elimination helps for better strata control and avoids the drillers working in unsafe conditions, maybe under the loose coal roof. This CMT improves the quality of the coal extracted and increases the output per man shift (OMS) by reducing the deployment of face crew. It also reduces the accident as it is operated by remote and workforce exposure to faces is limited. The method also helps for better roof and side control, thus preventing side and roof fall danger. With the changing time now, continuous miners of different heights are available, which helps for optimum use of technology to mine out varying insitu height of coal seam. This paper discusses the performance of the CMT in the Sarpi mine and compares the technology available globally.

Application of Shallow-Hole Blasting in Improving the Stability of Gob-Side Retaining Entry in Deep Mines: A Case Study

The hanging of hard roof strata in the gob-side retaining entry in deep mines could lead to dynamic disasters. The pressure relief mechanism for the hard roof strata using shallow-hole blasting was investigated by a combined method of theoretical analysis, numerical simulation, and field test in the Sanhejian coal mine. The shallow-hole blasting model was established using LS-DYNA3D(Livemore software of explicit dynamics analysis code). The evolution and propagation law of effective stress induced by shallow-hole blasting was analyzed. The parameters related to shallow-hole blasting were determined via a combined method of numerical analysis and theoretical calculations. These were applied to the field tests. The effect of shallow-hole blasting on the strata control of deep gob-side retaining entry was studied by comparing two scenarios in the field: a deep gob-side retaining entry with and without shallow-hole blasting. It was found that the convergences of the entry decreased due to the shallow-hole blasting. This indicates that shallow-hole blasting is a good technique to maintain the stability of the gob-side retaining entry with a hard roof in deep mines.