Results 31 - 40 of 53

• Hydraulic Stimulation of a Surface Borehole for Gob Degasification
  1/1/1977 - Reports of Investigations
  The Bureau of Mines evaluated the hydraulic stimulation of a gob degasification borehole to determine if this procedure would aid in degasifying a longwall panel.
• Water Infusion of Coalbeds for Methane and Dust Control
  1/1/1977 - Reports of Investigations
  This Bureau of Mines report deals with water infusion of coalbeds, which can control methane emission at face areas during developmental mining and which may sometimes suppress dust. Studies show that water infused into the coalbed flows through the fra...
• Three Coal Mine Ventilation Studies Using Sulfur Hexafluoride Tracer Gas
  1/1/1976 - Reports of Investigations
  This report describes three coal mine ventilation studies by the Bureau of Mines in which sulfur hexafluoride (SF6) was used as a tracer gas.
• Degasification and Production of Natural Gas From an Air Shaft in the Pittsburgh Coalbed
  1/1/1976 - Reports of Investigations
  The Bureau of Mines conducted research to determine the effectiveness of long holes drilled in solid virgin coal in degasifying an area of the Pittsburgh coalbed showing that horizontal holes drilled into a virgin coalbed from the bottom of any shaft wi...
• Methane Gas Content of the Mary Lee Group of Coalbeds, Jefferson, Tuscaloosa, and Walker Counties, Ala.
  1/1/1976 - Reports of Investigations
  It is estimated that more than 1 trillion cubic feet of methane is contained within the coals of the Mary Lee Group in Jefferson, eastern Tuscaloosa, and southern Walker Counties, Alabama. It is calculated that approximately 90 pct of the methane is at ...
• Determining Cleat Orientation of Deeper Coalbeds From Overlying Coals
  1/1/1976 - Reports of Investigations
  Examination of several coalbeds in Walker County, Alabama, Cambria, Greene, and Fayette Counties, Pennsylvania, and Caleigh and Wyoming Counties, West Virginia, indicates that cleat orientations are similar throughout a vertical sequence of strata. Stud...
• 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...
• Commercial-Quality Gas From a Multipurpose Borehole Located in the Pittsburgh Coalbed
  1/1/1975 - Reports of Investigations
  This report describes a multipurpose borehole used for both degasification and the production of commercial-quality gas. The multipurpose borehole was drilled into a barrier pillar, and seven horizontal degasification holes and one pressure point hole w...
• Geologic Investigations of Underground Coal Mining Problems
  1/1/1975 - Reports of Investigations
  Geological surveys were completed in six coal mines to study the overall geology of the coalbed, and to use the resulting data to evaluate the influence of the geological characteristics of the coalbed on safe and efficient coal extraction.
• Rotary Drilling Holes in Coalbeds for Degasification
  1/1/1975 - Reports of Investigations
  Coal is a soft and brittle material. Drilling rates in the Pittsburgh coalbed using a drag bit exceed 3 ft/min at 2,500-pound thrust. However, maintaining the bit on a horizontal trajectory or parallel to bedding planes to attain lengths of 1,000 feet i...