TORONTO, Mar. 4, 2010 (Canada NewsWire Group) -- /CNW/ -- Dumont Nickel Inc. (DNI:TSX-Ven, DG7:FSE) is pleased to announce that its initial leaching tests have reported good metal extraction recoveries from representative samples of black shale from its Alberta polymetallic black shale projects.
Simple sulphuric acid leaching tests completed by Dumont reported recoveries from 36-hour leaching at 30oC as follows (results from 24-hour leaching at 50oC also shown in brackets): Mo-28% (51%); Ni-89% (70%); U-84% (67%); V-34% (51%); Zn-88% (70%); Cu-53% (57%); Co-86% (69%); Cd-93% (71%); Li-45% (58%).
The test results are significant as they serve to demonstrate: (1) that metals can be readily extracted from the black shales; (2) that recoveries, even though not yet optimized, are high enough to compel expansion of the testwork and to continue its advance toward scaled up benchtests and column leaching; and, (3) that metal recoveries can be enhanced by optimizing test conditions.
The samples were tested without any pre-treatment, and the current testwork is intended as a first step toward formulating optimum leaching parameters to enhance recoveries.
Three surface samples were tested by leaching in a 1% sulphuric acid solution without any sample pre-treatment. Samples were leached over a 36 hour period at 30oC, and a duplicate set was leached over a 24 hour period at 50oC. Solvent composition was monitored at select intervals throughout the testwork to assess leaching progress. Leaching was conducted while maintaining substantially constant pH ranging 1.2-2 (avg 1.7) by periodically re-acidifying the solvent. Analyses were completed of tails (residues) as well as a head sample to calculate overall metal recoveries. The samples were collected by Dumont during its 2009 surface sampling program.
Two of the samples leached (09ASH005S and 09ASH006S) achieved only partial extraction during the 36 hours of leaching, indicating that future tests would benefit from a longer leaching period. The third sample (09ASH004S) achieved extraction of the bulk of metals recovered within the initial 10 hours of leaching. Results announced above are from the foregoing sample, though results from the partial extractions are also appended at the end of this press release for reference. As suspected, the results demonstrate that while some of the metals leach better at higher temperatures (e.g.Mo,V,Li), others benefit from longer leach time (e.g.Ni,U,Zn).
Considerable other work is in progress which are expected to be completed by the end of March and April. This work includes bioleaching testwork being conducted by the Alberta Research Council and by the Bureau de Recherches Géologiques et Minières (BRGM), France's leading Earth Sciences public institution. BRGM is recognized worldwide for its expertise in biohydrometallurgy and the development of innovative processes applied to industrial scale bioleaching of metals from sulphides. Results from the foregoing work will be announced once completed and data verification/checking have been concluded. Work to follow once the current stage of studies are completed will consist of testwork to commence optimizing and tailoring leaching parameters toward enhancing metals recoveries.
Dumont is pleased with the progress it has made through its testwork programs during the past several months, some of which have already been expanded in response to favourable findings. Dumont is in the process of planning its 2010 field work programs to collect additional sample material and, encouraged by the leaching results, has started planning for a 2010-2011 winter drilling program to commence upgrading its two Potential Mineral Deposits identified at the Buckton and Asphalt Zones to classified resources.
The Qualified Person (QP) in connection with this press release and in respect of the Alberta polymetallic black shale projects is Shahé F.Sabag PGeo, President and CEO of Dumont, who is responsible for verification and quality assurance of the exploration data and analytical results set forth in this release. The leaching and analyses reported herein were performed by Actlabs, Ancaster, Ontario. Analyses are by ICP and MS after total sample dissolution, and by Na-peroxide Fusion. Actlabs is an SCC accredited analytical facility with ISO/IEC 17025 certification and CAN-P-1579 registration. Samples leached comprise 10gm aliquots. Duplicate analyses were completed of the head and tails samples, both of which were also analyzed by multiple methods for convergence testing. Data announced herein is the simple average of all of analyses for any given aliquot. Several internal analytical control standards and blanks were relied upon by Actlabs during its analytical work, all of which data has been reported to Dumont and reviewed by its QP. Due to small sample size and even smaller related tails/residues, estimated metal recoveries reported above might vary by + 5% (relative%). The Alberta Research Council has recently changed its name to Alberta Innovates Technology Futures.
Partial extraction results from Sample 09ASH005S: Simple sulphuric acid leaching recoveries from 36-hour leaching at 30oC are as follows (results from 24-hour leaching at 50oC also shown in brackets): Mo-28% (28%); Ni-79% (71%); U-72% (65%); V-38% (33%); Zn-80% (73%); Cu-39% (44%); Co-77% (70%); Cd-89% (78%); Li-40% (34%).
Partial extraction results from Sample 09ASH006S: Simple sulphuric acid leaching recoveries from 36-hour leaching at 30oC are as follows (results from 24-hour leaching at 50oC also shown in brackets): Mo-8% (15%); Ni-38% (51%); U-53% (69%); V-9% (19%); Zn-38% (54%); Cu-34% (48%); Co-55% (61%); Cd-86% (83%); Li-16% (28%).
Dumont continues to focus its efforts on its polymetallic black shale Properties in Alberta, and its carried interest in the recent diamond discovery from its Attawapiskat Property, Ontario.
Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.
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