Pre-concentration test results at Granada Gold Mine returns 6.0 grams per tonne gold
How do you turn low-grade gold mineralization into a higher grade result? By pre-concentrating the lower grade gold bearing rock.
That's what Granada Gold of Rouyn Noranda did to improve the grade of its gold content from ore taken from its Granada Gold project.
Pre-concentration drastically reduces the ore mass that reports to intensive downstream processing. The process uses gravity to recover mineral-bearing particles into a much smaller volume, significant savings in energy and operational expenses are achieved.
Granada's preliminary gravity separation study demonstrated the positive impact of pre-concentrating lower-grade, gold-bearing rock from its Granada Gold project in Rouyn-Noranda, Quebec.
The higher grades attained during the tests may have implications for the grade of future mill feed, the size of the gold deposit, and the costs associated with future mine production.
"These metallurgical results can further de-risk the project and provide additional processing options for the company, and they potentially expand the existing resource by lowering the average gold grade that could be mined and processed using pre-concentration by gravity separation," explained Frank Basa, Chairman and CEO of Granada Gold.
The preliminary gravity test work, part of a suite of tests on rock samples from the Current Resources at the Granada Gold Mine project, was conducted by industry leader Gekko Systems of Ballarat, Australia. Their innovative pre-concentration system increases recovery values, reduces ore mass and waste, reduces water use, lowers power requirements, and improves feed rates, all potentially meaning lower capital and operating costs for Granada along with higher recovery rates.
To summarize results, a 260-kilogram sample of low-grade drill core assaying 0.6 grams of gold per tonne was upgraded to 6.0 grams per tonne with a 60 percent overall recovery. The Gekko laboratory processed the sample by crushing through different size fractions, homogenized, and split according to standard lab practices. Gravity tests were conducted on coarse and fine fractions, approximately +600 µm and -150 µm, respectively.
A grade of 21 grams per tonne gold was achieved from the coarse size fraction, with a recovery of 40%, resulting in an upgrade ratio (conc./feed) of 35. The test result which recovered the most gold has a gravity concentrate grade of 6.0 grams per tonne gold with a gold recovery of 60 percent.
Management of Granada Gold understand that conventional mining and processing leave behind significant amounts of gold and other metals which could have potential economic value.
"As a result of this preliminary work, we believe that employing disruptive technologies on lower grade ore to pre-concentrate the mineralized material for process plant feed can be advantageous," said Basa. "This approach can be used to evaluate the potential to increase the gold resource and other recoverable metals which, in turn, will lower project capital and operating costs."
Granada Gold Mine Inc. continues to develop the Granada Gold Property near Rouyn-Noranda, Quebec. Approximately 120,000 meters of drilling has been completed to date on the property, focused mainly on the extended LONG Bars zone which trends 2 kilometers east-west over a potential 5.5 kilometers of mineralized structure. The highly prolific Cadillac Break, the source of more than 75 million plus ounces of gold production in the past century, cuts through the north part of the Granada property.
Additional information is available at www.granadagoldmine.com.