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Wednesday, 11 April 2012
Clifton Star Resources reports 83.5% gold recovery from Beattie tailings at Duparquet
Clifton Star Resources(CVE:CFO) said Wednesday that recent metallurgical test results showed that high gold recoveries from historical tailings at its Duparquet project in Quebec are possible.
These high recoveries are seen using a combination of conventional flotation, pressure oxidation and cyanidation, the company said.
The overall gold recovery from the tailings sample obtained from the historical Beattie tailings was 83.5 percent.
The tests are part of a larger metallurgical test program that previously led to average gold recoveries of 93 percent from core samples of the different gold zones of the Duparquet project, as announced in March.
The tailings tests announced today from the Beattie deposit at the project were from a sample that graded 1.18 grams per tonne (g/t) gold, which was recovered from Clifton's Duparquet historical tailings impoundments that have been in place since the cessation of mining and processing at the complex in the 1950s.
Approximately nine million tonnes of tailings were generated from historical flotation processing of Beattie ores. Gold was recovered from the flotation concentrate after roasting and cyanidation, the company said.
The results confirm that the historical Beattie flotation tailings may be treated by a conventional flow sheet of flotation and pressure oxidation, Clifton said, with cyanidation of both the pressure oxidation residue and the flotation tailings.
"The excellent gold recovery results obtained on the sample from the Beattie tailings imply that we will also evaluate the reprocessing of the Beattie gold bearing tailings in a Preliminary Economic Assessment Study (PEA)," said president and CEO, Michel Bouchard.
"This PEA will follow the upcoming NI 43-101 resource assessment report from Innovexplo, now expected in May of 2012, which will include an estimate of the Beattie tailings gold resource."
Clifton is continuing with the testing of the Duparquet gold zones at the SGS Lakefield Research facilities in order to generate sufficient operating parameters to be used in the upcoming PEA report.
The company is also undertaking an additional metallurgical test program to determine the most economical process to treat the mineralization, sending samples of bulk concentrate to Goldfields of South Africa. The program will test the BIOX technology as an alternative to pressure oxidation.
The BIOX process uses bacteria to catalyze the oxidation of pyrite and arsenopyrite prior to gold recovery by carbon-in-leach cyanidation. In addition, samples of bulk concentrate have been sent to Australia for testing of XSTRATA Technologies' Albion process, which uses fine grinding and neutral oxidation of pyrite and arsenopyrite prior to gold recovery by carbon-in-leach cyanidation.
Both series of tests are now at the final stage of completion, the company said, and Clifton expects to have the results in May.
The new NI 43-101 compliant resource report for the entire Duparquet project will move the Beattie and Donchester estimates under the same criteria and allow for one data bank for the whole deposit.
The Beattie area of the Duparquet project is currently estimated to contain 1.72 million inferred gold ounces at a cut-off of 0.67 g/t gold, all in pit resources, as opposed to the current cut-off of 1.5 g/t gold used in the NI 43-101 report for Donchester.