Prophecy Achieves Over 95% Nickel Recovery in Preliminary Results From Lynn Lake Bioleach Study by Mintek
February 18 2011 - 8:30AM
Marketwired
Prophecy Resource Corp. ("Prophecy" or the "Company") (TSX VENTURE:
PCY)(OTCQX: PRPCF)(FRANKFURT: 1P2) has received preliminary results
from its ongoing metallurgical study on the amenability of its Lynn
Lake resource to the bioleach process. The bioleach study is being
conducted by Mintek in South Africa and overseen by Andy Carter,
Manager of Metallurgical Engineering for Wardrop Engineering Inc.,
a Tetra Tech Company. Key findings of the results to date show that
nickel recoveries in excess of 95% can be achieved using only a
moderate grind and leach temperature, whereas high copper
recoveries generally require finer grinding and higher
temperatures.
Details:
In July 2010, Prophecy collected 3.7 tonnes of a representative
sample of ore from Lynn Lake and shipped it to Mintek in Randburg,
South Africa for study. Continuous pilot flotation tests produced a
bulk concentrate containing 5.3% nickel and 3.4% copper at 89%
recovery for both metals. This concentrate was used as the feed
stock for the bioleaching testwork. Laboratory testwork conducted
in 2008 by PRA associates showed that a separate nickel concentrate
of 9.2%, and a copper concentrate of 7.5% could also be
produced.
The nickel in the concentrate occurs as pentlandite and
violarite, while the copper is present as chalcopyrite. Bioleach
amenability test work was performed in fully-controlled
continuously operated multi-stage reactor systems using microbial
cultures which have been adapted at Mintek to perform optimally
under the required operating conditions. The final metal
extractions were calculated based on analysis of samples obtained
from each of the reactor stages after achievement of steady state
conditions. The process was staged over a cumulative residence time
of just 6 days.
A process flowsheet is envisaged that consists of fine
concentrate regrinding followed by bioleaching at either 45 degrees
C or 70 degrees C. The parameters used for the study to date will
guide the optimisation of the processing route for concentrate
production and downstream processing to a saleable product.
Conclusion:
Mintek's results show a marked improvement in nickel recoveries
by as much as 6.5% compared to a previous lab bioleach study by PRA
Associates in 2008. While preliminary, the results indicate that
the Lynn Lake sulphide ore is highly amenable to the bioleach
process. Further process optimisation is currently underway. The
nine month long study is expected to be completed by June of this
year. Full results will be incorporated in a feasibility study to
be commenced later this year.
Lynn Lake and Bioleach Background:
The Lynn Lake mine was operated by Sherritt-Gordon from 1953 to
1976 and ranked as the third largest nickel producer in North
America, after only the Sudbury and Thompson mining camps.
Wardrop Engineering Inc., a Tetra Tech company, in a National
Instrument 43-101 report dated May 6, 2010 (available under the
Company's profile at www.sedar.com), estimated Lynn Lake to contain
a Measured and Indicated resource of 22.9 million tons at 0.57%
nickel and 0.3% copper, and an Inferred resource of 8.1 million
tons at 0.51% nickel and 0.28% copper. (0.4% nickel equivalent
cutoff) as outlined in the following table.
---------------------------------------------------------------------------
Mineral Resource Estimate for Lynn Lake (at a cut off of 0.4% NiEQ%)
---------------------------------------------------------------------------
Ni Cu Ni Cu
Tons Grade Grade Contained Contained
Resource Category (millions) (%) (%) lbs lbs
---------------------------------------------------------------------------
Measured and
Indicated 22.9 0.57 0.30 262,480,801 137,502,679
---------------------------------------------------------------------------
Inferred 8.1 0.51 0.28 81,560,064 45,615,427
---------------------------------------------------------------------------
The above resource estimate does not include the recent Disco
Zone discovery located within 1.5 km of the outlined resource. The
Lynn Lake project has immediate access to electrical power and rail
transportation and can be operated year-round.
Prophecy Resources is examining the bioleach- SX/EW option in
lieu of a direct smelter take-off for its Lynn Lake nickel-copper
concentrate. Bioleach SX/EW offers a proven, less expensive and
greener alternative to smelting. A bioleach SX/EW process, as part
of a fully integrated nickel operation will permit pure nickel to
be produced on site without transportation of concentrate and
costly smelter penalties. Currently bioleaching is being used with
commercial success in Finland (Talvivaara), China (Laizhou) and
Chile (Escondida). Owing to the exothermic nature of the reactions,
cold weather has a negligible effect on the process as demonstrated
at Talvivaara. In contrast to Talvivaara, which is a heap
bioleaching process, Prophecy plans utilising a tank based bioleach
reactor system.
Mintek
Mintek is based out of South Africa and has successfully
completed bioleach processes at the commercial level. They are
industry leaders in the field, with 25 years experience. Commercial
level implementation of this process for base-metals include the
Mount Lyell copper mine in Tasmania, and a 500kg per day pilot
plant at Industrias Penoles' facility in Monterrey, Mexico, during
2001; the plant has produced more than 40 t of LME A-grade cathode
copper from a complex polymetallic, chalcopyritic feed
concentrate.
For more information about Prophecy, please contact Paul
McKenzie at +1.604.642.2625 ext. 107 or John Lee at
+1.800.851.1528.
This news release has been reviewed and approved by Danniel
Oosterman, PGeo, Prophecy Geologist who is a Qualified Person as
defined in NI 43-101. The material in this news release has been
reviewed and approved by Andy Carter, a Qualified Person as defined
by NI 43-101.
About Prophecy Resource
Prophecy Resource Corporation is an internationally diversified
company engaged in developing energy, nickel and platinum group
metals projects. The company controls over 1.4 billion tons of
open-pittable thermal coal in Mongolia (839 Mt Measured, 579 Mt
Indicated). Prophecy's Ulaan Ovoo coal mine is fully commissioned
and in production. In Canada Prophecy owns Wellgreen PGM Ni-Cu
Project in Yukon, Lynn Lake Nickel Sulphide Project in Manitoba,
and a 10% equity stake in Victory Nickel. Mineral resources that
are not mineral reserves do not have demonstrated economic
viability.
ON BEHALF OF THE BOARD OF DIRECTORS of Prophecy Resource
Corp.
John Lee, Chairman
Forward Looking Statements: This news release includes certain
statements that may be deemed "forward-looking statements". All
statements in this release, other than statements of historical
facts, including, without limitation, statements regarding future
plans and objectives of the companies are forward-looking
statements that involve various risks and uncertainties. Although
Prophecy believes the expectations expressed in such
forward-looking statements are based on reasonable assumptions,
such statements are not guarantees of future performance and actual
results or developments may differ materially from those in the
forward-looking statements. Forward-looking statements are based on
a number of material factors and assumptions. Factors that could
cause actual results to differ materially from those in
forward-looking statements include general economic, regulatory,
market or business conditions, and other risks detailed herein and
from time to time in the filings made by the companies with
securities regulators. Mineral exploration and development of mines
is an inherently risky business. Accordingly the actual events may
differ materially from those projected in the forward-looking
statements. For more information on Prophecy and the risks and
challenges of its business, investors should review filings that
are available at www.sedar.com.
This press release does not constitute an offer to sell or a
solicitation to buy any of the securities in the United States. The
securities have not been and will not be registered under the
United States Securities Act of 1933, as amended ("the U.S.
Securities Act") or any state securities law and may not be offered
or sold in the United States or to U.S. Persons unless registered
under the U.S. Securities Act and applicable state securities laws
or an exemption from such registration is available.
"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."
Contacts: Prophecy Resource Corp. Paul McKenzie +1.604.642.2625
ext. 107 Prophecy Resource Corp. John Lee +1.800.851.1528
john@prophecyresource.com www.prophecyresource.com
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