Tyhee Gold Corp., through its 100% owned subsidiary, Tyhee NWT Corp., commissioned a feasibility study for its Yellowknife Gold Project located in the Northwest Territories, Canada. The feasibility study was prepared by a team of consultants that included SRK Consulting (U.S.), Inc, Lyntek Incorporated, Knight Piésold and Co. and EBA, a Tetra Tech Company. The feasibility study and NI 43-101 technical report were issued on schedule during September 2012 and demonstrated proven and probable ore reserves of 20 million tonnes at an average grade of 2 g/t Au.
As part of this study, SRK designed and supervised a feasibility-level metallurgical development program that was conducted on master composites and variability composites from the Ormsby, Nicholas Lake and Clan Lake ore deposits. Based on these studies, SRK recommended a process flowsheet that includes:
- three-stage crushing
- ball mill grinding
- gravity concentration of the coarse gold
- gold flotation from the gravity tailings
- cyanide leaching of gold flotation concentrate
- cyanide detoxification of the cyanidation residue
- tailings thickening
In the SRK-recommended process flowsheet, gravity concentration of coarse gold values followed by flotation of the remaining gold values into a flotation concentrate results in a very compact process plant in which only five weight percent of the initial ore is subjected to cyanidation.
Gold recoveries for Ormsby, Nicholas Lake and Clan Lake have been developed from the results of both locked-cycle testwork and from bulk gravity/flotation tests that were conducted on each of the test composites to produce flotation concentrates for regrind and cyanidation testwork. Gold recoveries for the Ormsby and Clan Lake deposits are projected at 92% and gold recovery for the Nicholas Lake deposit is projected at 82%. Additional testing is planned for the Nicholas Lake deposit to further assess ore character and process parameters that could potentially increase gold recoveries for the Nicholas Lake deposit.
SRK would like to thank Tyhee for their permission to discuss the Yellowknife Gold Project in this edition of SRK News.
