Mining Publication: Drainage of Methane From the Overlying Pocahontas No. 4 Coalbed From Workings in the Pocahontas No. 3 Coalbed
The Bureau of Mines conducted an experimental degasification project in Island Creek Coal Company Virginia Pocahontas No. 5 Mine. Methane from the overlying Pocahontas No. 4 Coalbed was entering mine workings in the Pocahontas No. 3 Coalbed through fractures in the roof rock. Small-diameter (1-5/8-inch) holes were drilled into the overlying coalbed to reduce the gas pressure and intercept methane flows, which were piped to the surface through an underground 6-inch- diam steel pipeline. The total methane flow rate from the vertical holes averaged 150,000 ft3/day for the first month. Methane flows into the mine were reduced by 47 pct, thereby demonstrating the effectiveness of this form of degasification in reducing ventilation requirements and providing a safer working environment.