Study of strata behaviour in longwall workings

摘要

Coal has been one of the energy resources of the country and it is extracted from earth crust by different methods. Longwall mining is the most popular and productive method of coal mining in the world. Majority of the longwall mines in India have not become as successful as they were envisaged. The main reasons for the underperformance of the longwalls in India, among others, have been strata control problems due to inadequate geological and geotechnical assessment, poor understanding of strata behaviour and selection of under rated supports. Complex strata mechanics issues like excessive stress concentrations, strata dilation or convergence of roof strata in longwall workings are potential hazard of strata failure. Therefore, proper understanding of geo-mechanics of strata and continuous strata monitoring in longwall workings is prerequisite for its effective control and ensuring safe workings. This paper discusses the strata control problems in Indian longwall mines and presents the instrumentation for strata monitoring. It also suggests a general scheme of strata monitoring in a longwall workings and explains a case study.