Results 11 - 20 of 20

• Electromagnetic Technique for Locating Boreholes
  1/1/1978 - Reports of Investigations
  The Bureau of Mines has developed hardware for electromagnetic (EM) detection and location of miners trapped in underground coal mines. This report describes a technique for using the developed equipment for locating uncased boreholes underground.
• Methane Drainage: Experience With Hydraulic Stimulation Through Slotted Casing
  1/1/1978 - Reports of Investigations
  The Bureau of Mines examined the wellbore of a vertical gas drainage well in the Mary Lee coalbed to determine the results of specific completion procedures in coal. A jet-slotting tool was used to cut four vertical slots through the casing about 1 ft b...
• 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.
• 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...
• 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...
• Two-Phase Flow in Coalbeds
  1/1/1975 - Reports of Investigations
  This report reviews experimental evidence indicating a relative permeability effect that causes the flow of methane to increase with time when a coalbed is degassed by boreholes.
• Hydraulic Stimulation Increases Degasification Rate of Coalbeds
  1/1/1975 - Reports of Investigations
  Coal degasification boreholes drilled from the surface have been successfully hydraulically stimulated to increase the flow of gas from the coal. This Bureau of Mines report describes the hydraulic stimulation procedure for a coalbed, the equipment requ...
• 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...
• Removing Methane (Degasification) from the Pocahontas No. 4 Coalbed in Southern West Virginia
  1/1/1963 - Reports of Investigations
  Tests were conducted in the Pocahontas No. 4 coalbed in southern West Virginia to determine if successful degasification techniques, developed during an earlier study in the Pittsburgh coalbed, would effectively remove methane from those usually more ga...