Results 1 - 6 of 6

• Behavior of Simulated Longwall Gob Material
  1/1/1993 - Reports of Investigations
  This report presents results of a U.S. Bureau of Mines study of longwall gob material. The objective of this work was to determine material stiffness properties of the gob for use in numerical models or rock mass response to longwall mining.
• Determining the Source of Longwall Gob Gas: Lower Kittanning Coalbed, Cambria County, PA
  1/1/1992 - Reports of Investigations
  Four coreholes were drilled at a longwall mine in the Lower Kittanning coalbed to obtain coal and rock samples from overlying strata to determine their gas content during the mining cycle. Test results indicate that 91% of the gas came from coalbeds.
• 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...
• Underground Gob Gas Drainage During Longwall Mining
  1/1/1982 - Reports of Investigations
  The Bureau of Mines is developing underground gob gas drainage as an alternate means of methane control for U.S. longwalls. Holes are drilled into the roof over the panel and on retreating longwalls, towards the working face from a location inby the fac...
• Longwall Gob Degasification With Surface Ventilation Boreholes Above the Lower Kittanning Coalbed
  1/1/1976 - Reports of Investigations
  Methane emission from two surface gob-degasification boreholes was measured by the Bureau of Mines. The investigation took place during mining of a 3,200-foot longwall panel in the Lower Kittanning coalbed in central Pennsylvania. The first hole was 500...
• Effect of a Surface Borehole on Longwall Gob Degasification (Pocahontas No. 3 Coalbed)
  1/1/1972 - Reports of Investigations
  The use of a partially slotted 6.5-Inch-inside-diameter vertical pipe to remove methane from a longwall gob area at a depth of 2,260 feet in the Pocahontas No. 3 Coalbed was investigated. The value of gas removed by such a pipe under free-flow condition...