Potential Hazards of Methane Gas in Oil Shale Mines.
Proc Envir Oil Shale Symp Colorado School of Mines Denver 1975 70(4):19-27
A Bureau of Mines technique for measuring the methane content of virgin coalbeds by degassing exploration drill cores has been used to estimate the methane content of oil shales. One site, where the core hole was about 1/4 mile from an outcrop, showed negligible gas. However, at another site where the core hole was 2 1/2 miles from the outcrop, the shale contained about 16 cubic feet of methane per ton. It is doubtful that a simple comparison will allow a prediction of methane emission from oil shale mines; however, it does appear that deep oil shale mines located some distance from outcrops may have methane gas to contend with. The deep trona mines of southwestern Wyoming are gassy, and this gas is believed to originate in oil shales that are interbedded with the trona. Also because oil shale mines will have large entries and relatively low air velocities, the tendency of methane to accumulate in layers may result in additional difficulties.
Proc. Envir. Oil Shale Symp., Colorado School of Mines, Denver, V. 70, No. 4, 1975, PP. 19-27