Prototype borehole miner selectively extracts gold from permafrost

Details

• Corporate Authors:
  National Institute for Occupational Safety and Health. Pittsburgh Research Laboratory
• Description:
  "Assess the technical feasbility of mining small and/or deeply buried frozenplacer deposits from the surface through boreholes. Placer deposits in permafrost often contain up to 15% cobbles and boulders. Because of erratic loading on the bit caused by elasticity and heterogeneity of the ice-and-gravel matrix, these deposits are extremely difficult to excavate. The approach taken in this research project was to mine only the ore-bearing portion of the deposit using a high-pressure water jet to thaw the gravels and a downhole hydraulic-lift-type pump to bring the ore to he surface as slurry. Full-scale jetting tests in frozen gravel were completed, and the data were used to design a jet excavator. The excavator will deliver a water flow of 890 L/min through a 15.7 mm diam nozzle at 6,900 kPa. The prototype slurry pump was designed to lift minus 15 cm gravels to the surface from a depth of 15 m." - NIOSHTIC-2
  
  NIOSTHTIC no. 20000466
  
  
• Subjects:
  Mining Occupational Health Safety
• Series:
  Mining Publications
• Subseries:
  Technology News
• Document Type:
  Text
• Genre:
  Newsletter
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  2 pages
• NIOSHTIC Number:
  nn:20000466
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:fb50b4fd86ead9e82db339130c12e6c815f711f2499ab3dec9ead61671a8ce8d730c39cf9578caa103b3c64c72382c8e977744768eb439f9ece71ea24e654af7
• Download URL:
  https://stacks.cdc.gov/view/cdc/9836/cdc_9836_DS1.pdf
• File Type:
  [PDF - 248.24 KB ]