Development of a Novel Mining Method for Coal Extraction at Higher Depth Using Continuous Miner Technology: A Perspective for Indian Coal Mines

Abstract

The application of continuous miner technology in Indian coalfields has demonstrated satisfactory performance for coal extraction up to depths of approximately 300 m. Its deployment at depths exceeding 300 m in certain mines in India, such as Churcha RO underground mine of Coal India Limited, VK-7, Vakilpalli mine, and Shantikhani of Singareni Collieries Company Limited, has revealed significant strata control challenges, adversely affecting the stability of underground structures and the roof. At higher depths, the increased and redistributed in-situ stresses compromise the effectiveness of the bord and pillar mining method. Notably, Indian coalfields contain an estimated 132.45 billion tonnes of coal reserves within the 300-600 m depth range, necessitating the development of efficient extraction strategies with safety. International experiences, particularly from Australia, indicate the successful utilization of continuous miner technology at depths up to 600 m through an alternative (Wongawilli method) of bord and pillar mining method. In this study, a stability investigation of underground structures of a seam sited at around 315 m depth at Godavarikhani 11 Incline Mine of Singareni Collieries Company Limited was examined through a finite difference-based three-dimensional numerical simulation study. An attempt has been made to address the limitations associated with continuous miner operation at a higher depth of cover. Based on the findings, a novel mining method is proposed for safe and efficient extraction of coal at higher depths using continuous miner technology for the selected mine. The proposed novel method was found to be techno-economically feasible and efficient for safe coal extraction at higher depths.