Assessment of status and extent of fire in abandoned coalmines – a case study

The problem of fire in abandoned mines is a global challenge to all coal producing countries. The main and immediate concern is t\o save the vital surface structures like railway lines/roads, bridges, rivers/stream, overhead construction from such fires as well as protecting adjacent underground property of the mine either by isolating or digging out permanently. But the difficulties are being faced, in both the cases of isolation of such fires, due to lack of knowledge of exact location of fire in unapproachable mine as the surface evidence of fires may not be related by straight line paths to the source of combustion. Authors have identified three zones around fire viz., active fire zone, upstream zone (negative pressure zone) and downstream zone (positive pressure zone) on the basis of some parameters viz temperature, pressure by measurement through boreholes, gas composition, fire index ratio from results of air samples collected through boreholes and application of US mine Fire Diagnostic (MFD) model. Vector representation of trend of gas composition, borehole wise was also used in indentifying the different zones and their widths. This concept was applied for identifying different zones of fire affected area in one of the mine of Bharat Coking coal Limited (BCCL) Situated in Central part of India in state of Jharkhand. The details of methodology for measurement of parameters considered, particulars of the mine and experimental conditions, results of investigation and steps for calculation of status and extent of fires including rate of progress for some period have been covered in this paper