Past Experiences to Future-Safe and Efficient Mining: Insights from Continuous Miner-Based Mass Production Technology in Indian Coalfields

Abstract

Standard-height continuous miner (CM) based mass production technology was introduced in India at the Anjan Hill Mine of South Eastern Coalfields Limited in 2003. It offered new hope for enhancing underground coal production after successful trials of the technology in the Bord and Pillar method across three panels located at shallow depths in the Anjan Hill Mine. Over the past 22 years, this mass production technology along with low-height continuous miners has been implemented in around 40 underground mines across various coalfields, operating at depths of up to around 400 m. Its deployment is expected to expand further to help in achieving the annual underground production target of around 100 million tonnes. Average daily production has been observed at about 1,000 tonnes (with average advancement of 50 m) during development operations and 2,000 tonnes during depillaring. However, to make underground mining more profitable, improvements are required in the efficient utilization of the CM package, the management of strata control issues and gas burst at higher depths. Coal extraction in Indian coalfields using this technology has shown satisfactory performance under easy-to-moderately caveable strata. Nonetheless, structurally controlled instability remains a challenge, particularly during the development of unsupported cut-out distances in original or split galleries. These issues arise due to geological discontinuities in the immediate roof and weak beds at the roof-pillar interface. At greater depths, stress-induced instability during depillaring operations affects both performance and safety, occasionally leading to injuries and loss of coal. Considering that about 132.45 billion tonnes of reserves lie at depths of 300-600 m, this study addresses key challenges and proposes methodologies for safe and efficient extraction under diverse geo-mining conditions using continuous miner-based mass technology.