"The Bureau of Mines conducted drilling studies in the Pocahontas No. 3, the Pittsburgh , and a western coalbed to establish the gas migration characteristics for each. Gas pressures in the Pittsburgh coalbed were about 260 lb/in2 and in excess of 550 lb/in2 in the Pocahontas No. 3. Caving in drillholes prevented pressure measurements in the western coalbed. The Pittsburgh coalbed contained intersecting "clay veins" which formed gas pressure cells . Although these geological features hamper mining, they can be used t o control the flow of methane into a mine working. Methane control techniques are proposed for the Pittsburgh and Pocahontas No. 3 coalbeds." - NIOSHTIC-2 NIOSHTIC no. 10000177

Report

Stephen B. Thacker CDC Library collection
National Institute for Occupational Safety and Health