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- Equipment, tools, and parts:
- Rotary drills
- Document types:
- Reports of Investigations
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Results 1 - 3 of 3
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1/1/1988 - Reports of InvestigationsThis Bureau of Mines report investigates the horizontal trajectory of boreholes drilled in coalbeds using the rotary drilling technique.
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1/1/1985 - Reports of InvestigationsThis Bureau of Mines report describes and compares the procedures, capital investments, and operating costs of rotary and in-hole motor drilling techniques used to drain methane gas from the Pittsburgh coalbed in an underground mine located in southwest...
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1/1/1975 - Reports of InvestigationsCoal 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...
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Content source: National Institute for Occupational Safety and Health, Mining Program