Results 51 - 60 of 75

• 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.
• 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 ...
• Methane Emissions from an Advancing Coal Mine Section in the Pittsburgh Coalbed
  1/1/1976 - Reports of Investigations
  The methane emissions from an advancing coal mine section were continuously monitored for 120 days. During this time, the section advanced 2,000 feet into virgin Pittsburgh coalbed producing 54,565 tons of coal with a total methane emission of 91 millio...
• Geological Factors Affecting Methane in the Beckley Coalbed
  1/1/1976 - Reports of Investigations
  This Bureau of Mines study reviews the geological factors that affect methane in the Beckley coalbed in southern West Virginia, including overburden, coalbed structure, type and changes in lithology above and below the Beckley coalbed.
• 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...
• Measuring the Methane Content of Bituminous Coalbeds
  1/1/1975 - Reports of Investigations
  The methane content of virgin bituminous coalbed can now be measured accurately in the field with exploration core samples from vertical boreholes. The gas content of the coal per unit weight can be used either to design a mine ventilation system or to ...
• 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.
• Peak Methane Concentrations During Coal Mining: An Analysis
  1/1/1974 - Reports of Investigations
  Methane concentration peaks were measured at coal mine working faces during entry development. The statistical distribution of peaks was found to be normal or log normal depending on how well the methane was being mixed into the ventilation airstream.
• Tracer Gas as an Aid in Mine Ventilation Analysis
  1/1/1974 - Reports of Investigations
  The Bureau of Mines has successfully used sulfur hexafluoride (SF6) as a tracer gas to measure mine air flows under conditions where conventional methods have failed. SF6 was employed experimentally to measure accurately recirculation of return into int...
• Low-Temperature Evolution of Hydrocarbon Gases From Coal
  1/1/1974 - Reports of Investigations
  Although it is generally believed that coal formation occurred at temperatures below 200 deg c, most experimental work on gas formation from coal has been performed at temperatures between 200 deg and 1,000 deg C. The objective of this Bureau of Mines e...