The federal Bureau of Mines has developed a method to measure directly the gas content of coalbeds by testing cored coals collected in a standard fashion. These direct measurements of the gas content have been related to methane emissions from operating mines. This method makes it possible to determine the resource base of the gas contained in the coalbed and the effect of the emissions on the contained gas during mining. It was found that if there is sufficient gas in the coal to warrant degasification, then there are four methods of draining gas from coalbeds. These are (1) vertical boreholes, (2) horizontal boreholes, (3) slant holes, and (4) gob degasification holes.
1976 Symp. on the Geology of Rocky Mountain Coal, Denver, Colorado, April 26-29, 1976, PP. 121-136