Results 91 - 96 of 96

• Design of Surface Mine Haulage Roads - a Manual
  1/1/1977 - Information Circulars
  An updated Bureau of Mines manual for the design of surface mine haulage roads. Covers such aspects as road alignment, construction materials, cross slope, drainage provisions and more.
• 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...
• 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...
• Evaluation and Determination of Sensitivity and Electromagnetic Interactions of Commercial Blasting Caps
  9/1/1973 - Contract reports
  Six different types of blasting caps, mainly of the type used in coal mines, were evaluated to determine both their radio frequency and direct current characteristics.
• Gas Migration Characteristics of Coalbeds
  3/1/1969 - Technical Progress Reports
  The Bureau of Mines conducted drilling studies in the Pocahontas No. 3, the Pittsburgh, and a western coalbed to establish the gas migration characteristics for each.
• Blast Wave Propagation in Underground Mines
  2/1/1995 - Conference papers
  This project investigates the behavior of blast waves from the detonation of high explosives in an underground mine.