Application of continuous miner technology for extraction of deep seated coal seam under hard roof conditions – a case study of Churcha mine

Abstract

India is the second-largest leading coal-producing country in the world. One of the main reasons for this feat is attributed to the adoption of the latest technologies of mining. In the case of underground (UG) coal mining, one such technology is continuous miner (CM), a mass production technology. After the introduction of CM technology in UG coal mines, production, productivity and safety have improved drastically. This technology has performed well in most of the mines where they are deployed, as it provides great flexibility to orient mining layout and strategy in changing geo-mining conditions. However, there have been experiences of challenges in maintaining production, productivity and safety standards in the cases of mines practicing depillaring operations with CM under adverse and difficult strata conditions. One such unique experience is the case of achieving an outstanding performance of CM technology at Churcha mine (RO) of South Eastern Coalfields Limited (SECL), hereinafter referred to as Churcha mine, where two sets of caterpillar make CM package are deployed under a strata condition which is not favourable due to the coal seam being deep-seated under hard roof conditions overlain by a hilly terrain surface topography. Even the powered support longwall (LW) face with shearer and powered supports got collapsed in the past due to heavy weighting on the supports in this mine. This paper discusses the difficulties faced in operating CMs in this mine with a deep-seated coal seam under a hard sandstone roof and the corrective measures adopted to overcome those challenges to set a unique example of achieving an appreciable level of production, productivity and safety in the UG coal mining history of India.