Mine fire diagnostics in abandoned bituminous coal mines.
Dalverny-LE; Chaiken-RF; Kim-AG
Proc 1990 Mining & Reclamation Conf & Exhibition West Virginia Univ Pub Svc 1990 2:527-534
The U.S. Bureau of Mines is developing a mine fire diagnostic methodology to locate and monitor fires in abandoned coal mines and waste banks. The method assumes that (1) measurable changes in the emission of low-molecular-weight hydrocarbons from coal are directly temperature dependent, and (2) analysis of controlled underground airflow between borehole sampling points can determine the source of the hydrocarbons. A hydrocarbon ratio, r1, a signature for heated coal, is related to the relative concentrations of methane and total hydrocarbons (methane through pentane). An exhaust fan attached to a borehole creates underground pressure gradients that control the movement of gases past a network of borehole sampling points. Changes in r1 value are correlated with the assumed direction of gasflow between borehole pairs. Multiple tests with different orientations allow spatial definition of both heated and cold subsurface zones. The mine fire diagnostic methodology has been used to define noncontiguous combustion zones, locate cold boundaries in remote combustion areas, determine effects of extinguishment activities on the fire, and accomplish long-term monitoring. Results obtained at two abandoned bituminous coal mine fires are discussed.
Proc. 1990 Mining & Reclamation Conf. & Exhibition, West Virginia Univ. Pub. Svc, V. 2, 1990, PP. 527-534