Results 1 - 3 of 3

• Comparisons Between Cross-Measure Boreholes and Surface Gob Holes
  1/1/1986 - Reports of Investigations
  The Bureau of Mines conducted studies to compare the effectiveness of the cross-measure borehole system with that of surface gob holes on two successively mined retreating longwalls in the Lower Kittanning coalbed. Only the cross-measure system was in o...
• Methane Control on Longwalls with Cross-Measure Boreholes (Lower Kittanning Coalbed)
  1/1/1985 - Reports of Investigations
  The cross-measure borehole technique is an effective method of controlling methane liberated by fracturing the roof strata in longwall gobs where overburden is less than 750 ft (229 m). About 71 pct of the methane produced by longwall mining in the Lowe...
• Control of Longwall Gob Gas With Cross-Measure Boreholes (Upper Kittanning Coalbed)
  1/1/1983 - Reports of Investigations
  The cross-measure borehole technique is being studied as an alternative to the use of surface gob boreholes as a means of controlling methane in gobs during longwall mining. Small-diameter holes are drilled from underground locations into strata overlyi...