Removing Methane from Coalbeds in Advance of Mining by Surface Vertical Boreholes.
In Proc Conf on Underground Mining Environment Univ of Missouri Rolla 10/71 PP 209-228 :209-228
Because of the need to mine deeper and more gaseous coalbeds at increasingly higher rates to meet the demand for coal, it is increasingly more difficult to provide a sufficient quantity of air to dilute the gas emitted at the working face to a safe concentration. An alternative to greater ventilating air volumes is degasification of the coalbed to lower methane emission rates. One technique for degasifying a coalbed is through the use of surface boreholes drilled from the surface into the coalbed in advance of underground mining. This paper summarizes experience in degasification by surface boreholes in three major coalbeds--the Pittsburgh, the Pocahontas No. 3, and the Mary Lee--and presents data on the properties and characteristics of these coalbeds.
In Proc., Conf. on Underground Mining Environment, Univ. of Missouri, Rolla, 10/71, PP. 209-228