Report of Investigations 9239: Evaluation of Moderately High-Pressure Water-Jet Assist Applied to Single Drag Bit Tools

Details

• Journal Article:
  MISSING
• Personal Author:
  Thimons, Edward D. ; Thompson, J. L. ; Timko, Robert J.
• Description:
  The U.S. Bureau of Mines conducted a water-jet-studies program using a single-bit, in-seam test unit to determine effects of a moderately high-pressure (up to 10,000 psi) water-jet-assisted cutting system on rock weakening. The in-seam test unit was used to obtain cutting force data in tangential, normal, and side force directions. Conical continuous miner and radial longwall miner bits were used to penetrate test samples of coalcrete, Berea sandstone, and Indiana limestone with unconfined compressive strengths of 4,600, 8,000 and 10,000 psi, respectively. Depth of cut in the coalcrete tests was 1 in, with 2-in cut spacing (2:1 ratio). Because of cutting equipment and instrumentation limitations, the Berea sandstone and Indiana limestone were cut using a 0.5-In depth of cut and 2-in spacing (4:1 ratio). Bit velocity was maintained at 25 ft/min for both bits. Each specimen and bit type was tested using 0.3-, 0.6-, 0.8-, And 1.0-Mm-diam nozzles and water-jet pressures of 2,500, 5,000, 7,500, and 10,000 psig. Water-jet-assisted cutting decreased average resultant conical and radial longwall bit cutting forces 6.4 and 8.4 pct in coalcrete, 5.5 and 1.4 pct in Berea sandstone, and 2.0 And 5.5 pct in Indiana limestone. Slight reductions of power requirements resulting from water-jet assist were ascertained during these experiments. [Description provided by NIOSH]
• Subjects:
  Mining Occupational Health Safety
• Source:
  MISSING :11 pages
• Series:
  NIOSH Numbered Publications   ; Mining Publications  
• Subseries:
  Report of Investigations
• Document Type:
  Text
• Genre:
  Report
• Place as Subject:
  Indiana ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PRC - Pittsburgh Research Center
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  16 pdf pages
• NIOSHTIC Number:
  nn:10006978
• Federal Fiscal Year:
  1989
• Peer Reviewed:
  False
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:ea46de4978e4f1e9a4c56d987611a3d1f638abe6a803fc907103b1309ffa8aca0f4b9c785577b342217c17271535e966c06309a45b391b2c52e26fd225e4a835
• Download URL:
  https://stacks.cdc.gov/view/cdc/10470/cdc_10470_DS1.pdf
• File Type:
  [PDF - 6.06 MB ]