The use of nuclear tracers to evaluate the gold recovery efficiency of sauceboxes

Abstract
Sluiceboxes can provide a much higher concentration ratio than most other gravity concentrators (up to 50 000:1) at very high overall placer gold recoveries (greater than 99%). They are also very reliable, inexpensive and simple to operate. This combination is very difficult to beat and explains why the sluicebox is still the most important placer gold concentrator in Canada's Yukon Territory.
A sluicebox is a rectangular flume containing riffles on matting, through which a dilute slurry of water and alluvial gravel flows. Sluiceboxes operating under ideal conditions are actually centrifugal concentrators whose riffles overturn ribbons of slurry to form vortices. At the bottom of these vortices, centrifugal and gravitational forces combine to drive placer gold particles into matting.
Testing sluiceboxes with conventional sampling and evaluation techniques is very costly, time consuming and problematic. The effect of a single gold particle can cause large unpredictable errors (nugget effect) even when large sample volumes are processed with care. Nuclear tracer tests are more accurate, faster, cheaper and safer than conventional sampling.
In 1989 through 1991, the recovery efficiency of several sluicing systems was determined by mixing radioactive gold particles (tracers) into the feed streams of 27 placer mines in the Yukon Territory. Four distinct sizes of nuclear tracers were used and their recovery was related to the design and operational characteristics of the individual sluiceboxes and their pay gravels.
Over-all gold losses ranged between 71% and 0, or from $2.5 million to less than $1000 per 1200 hour season. One of the triple-run sluiceboxes and one of the single-run boxes lost more gold than they recovered. The sluiceboxes which were fed with pre-screened gravels (minus 25 mm) had the lowest losses of all, averaging only $47,000 per season. Three of these sluiceboxes recovered 99% of their gold.
Many of the mine recovery plants tested in 1990 had already implemented recommendations from the 1989 test program including the use of unbacked Nomad matting, coarse expanded metal and 25 mm angle iron riffles. None were using doubled expanded metal riffles and few were using cocoa matting or Monsanto matting. Four operators installed screening equipment which increased their gold recovery by 10% to 20%. Another four operators modified their sluicing systems and increased their gold recovery by 3% to 44%. This paper presents a summary of the existing and potential gold recoveries, and recommends sluicebox designs and operating parameters based on the results of nuclear tracer testworkfrom 1989 through 1991, conventional sampling in 1988 and laboratory investigation in 1989-1990.
Keywords: Gold recover, Mineral processing, Nuclear tracers, Sluiceboxes.
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Publication: CIM Bulletin
Author(s): H. Kalsi
Keywords: Gold mining, Underground mining, Water control.
Issue: 979
Volume: 87
Year: 1994
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Summary: Survival in today's business climate requires participation of all employees in a Total Quality Management Program encompassing everything & mdas "safety, quality of products, quality of each and every job done, and of course production".
Publication: CIM Bulletin
Author(s): S. Brown
Keywords: Human resources, Management.
Issue: 979
Volume: 87
Year: 1994
Text
Summary: A hydrocyclic system used for mineral separation at the laboratory scale results in the separation of more than 90% of micas. The system functions only by water and might offer advantages where other methods of mica separation are not available.
Publication: CIM Bulletin
Author(s): Alijan Aftabi, Alireza Sarafi
Keywords: Mineral separation, Hydrocyclic systems.
Issue: 979
Volume: 87
Year: 1994
Text
Summary: Mining research at CANMET is delivered by the Mining Research Laboratories Division (MRL), with facilities in Sydney, Nova Scotia; Bells Corners, Elliot Lake, and Sudbury, Ontario; and Val d'Or, Quebec. This paper gives an overview of the work of the Division as of early 1993. An addendum, at the end of this paper, describes the organizational changes that will take place in April 1994.
Publication: CIM Bulletin
Author(s): John E. Udd
Keywords: Backfill, CANMET, Explosives testing, Explosive atmospheres, Mining Research Laboratories, Mining environments, Research and development, Rock mechanics.
Issue: 979
Volume: 87
Year: 1994
Text
Summary: The process of arriving at the size and grade of: (a) a newly-discovered body of mineralization, (b) a potential ore resource, (c) an orebody proposed for mining, or (d) the ore reserves in a mine, requires fundamental geological, and geometrical determinations as well as physical and chemical analyses. This paper outlines geological and geometrical features considered critical, in the authors' experience, in realistic reserve determination. These are discussed under the headings "The...
Publication: CIM Bulletin
Author(s): O. Owens, W.P. Armstrong
Keywords: Ore reserve estimation, Geology, Mineralization.
Issue: 979
Volume: 87
Year: 1994
Text
Summary: Backfill practices at the Williams mine have evolved significantly since underground mining began in 1986. The use of conveyors as a means of transporting fill material to slopes has been discontinued in favour of load-haul-dump equipment. The method of adding binder to the fill product has been refined along with the placement technique. Slurry preparation has been fully automated and flyash is now included as a binding agent. Surface preparation of the fill product has evolved substantially...
Publication: CIM Bulletin
Author(s): J. Rheault, D. Bronkhorst
Keywords: Backfill practices, Underground mining, Williams mine, Rock-fill properties.
Issue: 979
Volume: 87
Year: 1994
Text
Summary: Fording Coal is a wholly owned subsidiary of Canadian Pacific Limited. The company was founded in 1968 to mine metallurgical coal for export at the Fording River operations in southeast British Columbia.
Today, Fording Coal Limited also operates the Whitewood mine under contract to TransAlta Utilities and the Genesee mine under a joint venture arrangement with Edmonton Power. Both these operations are located just west of Edmonton and produce sub-bituminous low-sulphur coal which is used for...
Publication: CIM Bulletin
Author(s): E. Wusaty
Keywords: Coal mining, Open pit mining.
Issue: 979
Volume: 87
Year: 1994
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