TORONTO, Nov. 16, 2017 /CNW/ - Kerr Mines Inc. (TSX: KER, OTC: KERMF, FRA: 7AZ1) ("Kerr" or the "Company") is pleased to announce positive initial metallurgical results including an evaluation into the accretive recovery of copper from gold bearing zones for the upcoming Prefeasibility Study.
Highlights
- Gold recoveries up to 91%
- Copper present throughout the strike length of the Copperstone Zone
- Monetization of both sulphide and oxide copper content being examined
- Sulphide copper recovery up to 97%
- Oxide copper metal extractable from flotation underflow through a simple acidulation process
Gold
The initial results of the gold testing to date achieves recovery of up to 91%. The testing methods used are based on the existing processing circuit at the Copperstone project.
The samples being tested can be categorized as low, medium and high grade gold samples across the entire strike length of the Copperstone Zone. Processing alternatives are being evaluated to further enhance recovery of gold including whole ore leaching, flotation and a combination of flotation and gravity. Flotation test results to date have excellent gold recoveries and also confirm historical results.
Copper
For the first time, work is underway to determine and report a copper resource for the Copperstone Project. Of historic and new drill hole intervals which contain a gold grade of 3 g/t Au or higher and that were assayed for copper, the weighted average copper grade is 0.54% Cu. Copper assay values are distributed along the entire strike length of the Copperstone Zone. In that volume, over 90% of the time that gold is present, copper is present as well.
Current studies show that both sulphide and oxide copper exists in the Copperstone Project. Feed grades up to 0.68% Cu were represented in the group of samples. When sulphide copper is present, a copper recovery up to 97% to the gold rougher flotation concentrate is achievable. Oxide copper reports to the underflow of the flotation circuit, as such, there exists an opportunity to create a feed of copper to a simple acid processing circuit. It is in this new circuit that the oxide copper would be extracted and recovered as a metal. The economic viability of both potential copper revenue streams requires further testing and is underway.
Martin Kostuik, President, stated, "with these initial Copperstone metallurgical results and the new understanding of the two potential streams of copper within the processing circuit, we are very encouraged to investigate the potential for copper to enhance the economics of this project. The recovery of copper from the flotation underflow would be relatively low cost because the other aspects of the copper recovery process are paid for in the gold recovery circuit."
The Copperstone Zone detachment fault system historically produced over 500,000 ounces of gold from an open pit. Continuing below the open pit, the down-dip extension of the Copperstone Zone has an undiluted mineral resource of 313,000 oz Au at 10.35 g/t Au (0.302 ounce per ton) (311,000 measured + 2,000 indicated), estimated in 2010* is being further enhanced by the Phase 1 underground drilling program. The Phase I 15,000 feet underground program is currently using two drills to test along strike and up/down-dip in the D and C zones of the Copperstone Zone. The program is confirming altered detachment fault breccia continuity from existing underground workings at depths from 100 to 400 feet below the open pit bottom.
The technical information in this news release has been prepared in accordance with the Canadian regulatory requirements set out in NI 43-101 and reviewed and approved by Michael R. Smith, Registered Geologist., who is a "Qualified Person" as defined by NI 43-101 for this project.
