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Technology News 460 - prototype borehole miner selectively extracts gold from permafrost.

Authors
Savanick-GA; Miller-AL
Source
NIOSH 1997 Jul; :1-2
NIOSHTIC No.
20000466
Abstract
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.
Keywords
Mining-industry; Jet-Pumps; Gravel; Slurry; Gold; Boreholes
Contact
National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, 626 Cochrans Mill Road, Pittsburgh, PA 15236
CAS No.
7440-57-5
Publication Date
19970701
Document Type
Technology News
Fiscal Year
1997
NTIS Accession No.
NTIS Price
Identifying No.
TN-460
NIOSH Division
PRL
Source Name
National Institute for Occupational Safety and Health
State
PA
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