Results 481 - 490 of 514

• Overlap Probability for Short-Period-Delay Detonators Used in Underground Coal Mining
  1/1/1985 - Reports of Investigations
  Investigation of coal-mine-type short-delay electric detonators to determine the delay accuracy and the probability of overlap between adjacent delay periods.
• Measuring Formation Pressures and the Degree of Gas Drainage in a Large Coalbed Gas Drainage Field
  1/1/1985 - Reports of Investigations
  The Bureau of Mines and United States Steel Corp. are conducting a joint project to monitor formation pressures at a large (23-well) coalbed gas drainage field near Oak Grove, Alabama. Three monitor holes were drilled in late 1981, and pressure monitori...
• Reverse Performance Characteristics of Main Mine Fans
  8/1/1983 - Open File Reports
  Laboratory and field tests of vane axial main mine fans in the 7- to 9-ft diameter size range were conducted to establish forward and reverse performance characteristics under controlled conditions and at typical mine installations.
• A Medium Frequency Wireless Communication System For Underground Mines
  1/1/1983 - Contract reports
  An underground medium frequency radio communications system has been developed and demonstrated in both coal and metal/non metal mines. The principal advantage of the system are its low cost, ease of installation and the ability to provide radio communi...
• Sulfur Hexafluoride as a Mine Ventilation Research Tool - Recent Field Applications
  12/1/1982 - Reports of Investigations
  Sulfur hexafluoride (SF6) is an odorless, colorless, nontoxic gas that has found acceptance as a tracer gas in research on ventilation patterns, measurement of air leak rates, respirable dust reductions due to bagging hood modifications, and the study o...
• Drilling a Horizontal Coalbed Methane Drainage System from a Directional Surface Borehole
  1/1/1982 - Reports of Investigations
  Three long horizontal holes were drilled from a directionally drilled surface hole at the Emerald Mine near Waynesburg, Pennsylvania. The purpose was to adapt the technique of directional drilling for use in draining methane from coalbeds.
• Geology of the Lower Kittanning Coalbed and Related Mining and Methane Emission Problems in Cambria County, Pa.
  1/1/1979 - Reports of Investigations
  The Bureau of Mines established geologic factors affecting the mining of the Lower Kittanning coalbed to aid in coalbed minability studies and examined the occurrence of "wants" (places where coal is missing) and types of unstable roof rock strata.
• Methane Absorption in Oil Shale and Its Potential Mine Hazard
  1/1/1977 - Reports of Investigations
  The Bureau of Mines made laboratory absorption measurements on oil shale samples, which showed that the amount of methane absorbed is proportional to pressure and oil yield, and can be much larger than would be predicted based solely on porosity. Oil sh...
• Methods of Determining the Orientations of Bedrock Fracture Systems in Southwestern Pennsylvania and Northern West Virginia
  1/1/1977 - Reports of Investigations
  This Bureau of Mines report describes photo-lineaments obtained from stereoscopic examination of vertical aerial photographs and by the ronchi grating study of aerial photoindex sheets. The photo- lineaments are compared with the trends of oriented frac...
• 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...