ONTARIO – Vancouver's Orefinders Resources released the results of metallurgical tests indicating an average 93% gold recovery from samples taken from its Mirado stockpile near Kirkland Lake. SGS Canada conducted the tests, including a determination of the Bond work index and cyanidation trials.
Four 30 kg samples were prepared. Each was subjected to standard Bond ball mill grindability tests, and the work index ranged from 15.4 to 18.3 kWh/t. Each sample was pre-aerated for 6 hours then leached for 48 hours with 1.0 g/L NaCN. The consumption of cyanide was low to moderate at 0.3 to 0.4 kg/t, and lime consumption was approximately 0.7 kg/t. Gold extraction ranged from 91.2% to 94.4% and averaged 93% at an average grind size of P80 of 65 μm.
Basic environmental characterization tests were also performed on a combined tailings sample. The tests determined that the tails would be classified as potentially acid generating. None of the regulated elements exceeded the Schedule 4 limits of the Metal Mining Effluent Regulations, according to Orefinders.
The three unprocessed stockpiles contain 20,742 tonnes averaging 4.41 g/t Au or 2,939 oz of gold. The material was extracted from the North and South Zones where Orefinders has reported an NI 43-101 inferred resource of 10.6 million tonnes at a grade of 1.29 g/t Au.
Visit Orefinders.ca to enjoy the Mirado photo gallery.