Directional Drilling for Coalbed Degasification in Advance of Mining.
Proc 2nd Ann Symp on Methane Recovery from Coalbeds Pittsburgh, Pennsylvania, 1979 Apr; :162-176
The Bureau of Mines has conducted research in directional drilling for degasification in advance of mining since 1973. This technique is designed to combine the highly successful underground horizontal degasification drilling technology with surface drilling methods. The use of directional drilling techniques will be particularly useful in areas where access to gassy coalbeds is not possible underground, and where topography makes multiple sites for vertical degasification holes impractical or prohibitively expensive. This report presents the development of the directional drilling technique in detail along with a description of the Bureau's current directional drilling program at the Emerald Mine near Waynesburg, Pennsylvania.
Proc. 2nd Ann. Symp. on Methane Recovery from Coalbeds, Pgh., Pennsylvania, Apr. 18-20, 1979, PP. 162-176