Huge drop in cap costs suggested by new study Clifton Star Produces High Grade Gold Concentrates from the Duparquet Project for Possible Toll Smelting
https://www.cfo-star.com/wp/wp-content/uploads/2013/03/Clifton-Star_High-Grade-Gold_PR_March-27-2013_Final.pdf
(excerpt)
Quebec City, QUEBEC–March 27, 2013 – Clifton Star Resources Inc. (“Clifton Star” or
“the Corporation”) (TSXV-CFO; Deutsche Boerse-C3T) is pleased to report that it has
received the results of a laboratory study conducted by SGS Minerals that succeeded
in producing high grade gold concentrates from mineral samples of the Duparquet
Project. Six samples from the Duparquet Project were treated using a cleaner flotation scheme developed by SGS Minerals to recover a high grade gold concentrate. The tests were performed as “locked cycle” tests to simulate full scale plant operating conditions.
Cleaner flotation tests were conducted to investigate the recovery of gold in a sulphide
concentrate for the purpose of toll smelting as an alternative to the operation of a
pressure autoclave (POX), which is part of the mill process flowsheet used in the
recently published preliminary economic assessment study (“PEA”) on the Duparquet
Project (press release dated January 15, 2013).
? The gold grade of the cleaner concentrates ranged from 39 g/t Au to 84 g/t Au
and the sulphur grade ranged from 21% S to 36 % S. These grades of gold and
sulphur are amenable to toll smelting through copper smelting operations.
? The average overall gold recovery was 89.6%. This overall recovery is close to the
93% overall gold recovery obtained with the pressure oxidation treatment of
lower grade flotation concentrates.
? The production of high grade concentrates raises the possibility of avoiding the
capital and operating cost of building a full scale pressure oxidation pretreatment plant for the Duparquet Project. The capital cost of the POX circuit in
the Tenova Bateman cost study, presented as part of the recent PEA, was $157.5
Million out of an estimated cost of $270 Million for the entire Mill. This cost
would no longer be required but there would be some much lower additional
costs for cleaner flotation, concentrate filtering, drying and shipping. Similarly,
the operating cost for the POX area of the mill was estimated at $6.67/t of ore.
This cost would not be required but would be substituted by the lower operating
costs for concentrate preparation and shipping.
A rougher concentrate was recovered following the conditions applied in previous test
work. In five out of six samples, only one cleaning stage was sufficient to produce
concentrate grades exceeding 35 g/t in gold. Arsenic content averaged 1.1 % for the six
samples and would imply a penalty since most smelters accept a 0.4% content.2
The reagent consumptions for cyanidation of the flotation tailing were 0.14 - 0.47 kg
NaCN/t of ore and 0.54 – 0.81 kg CaO/t of ore. These values are very low and indicate
that cyanidation of the tailings will consume minimum amounts of chemical reagents.
Pre-Feasibility Study on the Duparquet Project:
Clifton Star has started a Pre-Feasibility Study on the Duparquet Project and part of it
will compare the relative benefits of the two possible process treatments, either a POX
circuit, as used in the PEA, or production of high grade gold concentrates.
Between January and March, Clifton has gathered a new 12 tonne sample of the
Duparquet Project mineralized zones, from large diameter drill core. It was sent to SGS
Lakefield for metallurgical and environmental pilot tests in support of the upcoming PreFeasibility Study. The planned test work will include a continuous pilot plant test for POX
and also for high grade gold concentrates production. Tests are expected to be
completed in the 2nd quarter of 2013. Clifton Star will contact smelting companies and Commodity brokers to gauge the interest in toll treatment of the concentrates.
Qualified Person
Dr. David Dreisinger, P.Eng., F.C.I.M., F.C.A.E., is the Qualified Person (NI 43-101) who
supervised the preparation of the technical information in this news release. Dr.
Dreisinger is a Professor, and Chairholder of the Industrial Research Chair in
Hydrometallurgy at the University of British Columbia (Vancouver, Canada) and a
worldwide consultant for the metallurgical industry through Dreisinger Consulting Inc.
Additional Information
All other information previously released on Duparquet is also available on Clifton Star’s
website at www.cfo-star.com
For further information please contact:
Michel F. Bouchard
President and CEO
Clifton Star Resources Inc.
mbouchard@cfo-star.com
418-914-9922
www.cfo-star.com
Twitter: @cliftonstar1
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future exploration, financial or operating performance and other statements that
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‘forward-looking statements’ within the meaning of the ‘safe harbor’ provisions of the 4
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