Heat removal methods for control of underground abandoned coal mine fires.
Mine Drainage and Surface Mine Reclamation. Volume II: Mine Reclamation, Abandoned Mine Lands and Policy Issues. Vol. II. Pittsburgh, PA: U.S. Bureau of Mines, 1988 Apr; :343-347
The Bureau of Mines is conducting research to determine the effectiveness of several related techniques for the removal of heat from underground fires in abandoned coal mines. Mine fires are notoriously difficult and dangerous to extinguish because the heat becomes deeply seated in the coal and in the surrounding rock strata, and there can be potentially explosive gases near the heated material. Fire control methods which attempt to deprive the combustion zone of oxygen are ineffective, as the fuel can smolder indefinitely at <2 pct oxygen concentrations. Methods that excavate the coal seam produce extensive and expensive surface disruption affecting the landscape and surface structures. The Bureau has developed heat removal methods to remotely extract thermal energy from the underground fuel and adjacent heated rock strata. The mine then cools below the temperature needed to sustain combustion and negative effects on the surface are minimized. The Bureau techniques draw heated underground gases to the surface with an exhaust fan attached to a borehole into the mine. Water, detergent foams, or cryogenically liquified inert gases injected into the mine can enhance the energy-absorbing capacity of the subsurface gases. Two completed field trials have used water, injected as a spray or in a stream. A current project will use one or more foams to carry water and other chemicals to the burning material. Future activities may use cryogenic gases to both cool directly and remove heat indirectly via the exhaust fan.
Underground-mining; Mining-industry; Coal-mining; Fire-hazards; Occupational-hazards; Mine-fires; Fire-fighting; Fire-extinguishing-systems
IH; Conference/Symposia Proceedings
Mine Drainage and Surface Mine Reclamation. Volume II: Mine Reclamation, Abandoned Mine Lands and Policy Issues