As it works toward a feasibility study of the polymetallic McIlvenna Bay project in Saskatchewan, Foran Mining Corp. grew indicated resources 65% in terms of tonnage over a 2013 resource to 22.95 million tonnes grading 1.17% copper, 3.05% zinc, 0.19% lead, 0.44 g/t gold and 16.68 g/t silver.
"It's a better resource than, quite frankly, I initially expected," Foran President and CEO Patrick Soares said.
Soares said the resource bolsters the potential in a bulk mining scenario of the deposit's two main zones — the massive sulfide and copper stockwork zones — that comprise the majority of McIlvenna Bay's resources.
"It really does show us the massive sulfide zone is extremely continuous and cohesive," Soares said. "And the copper stockwork zone, which is adjacent, is also continuous."
The resource update came as Foran works toward a feasibility study of the project, one of Canada's larger undeveloped base metal deposits, that Soares said to expect by the end of the year. With an average combined width of 17.6 meters in the two main zones, Soares said the plan would be to bulk mine them together.
One key unanswered question is how strong metal recovery will be under a bulk mining scenario. Foran has not yet completed a metallurgical study of recoveries for a mine plan where different zones, previously treated separately, are potentially mined as one.
"The view is because of continuous mining, the massive sulfide would come down together, and the copper stockwork would come down together," Soares said. "And we're not sure how the copper stockwork and the massive would separate out, or whether they would at all."
Different mining approaches could also affect how the material is processed. If material was primarily trucked, it might be easier to separate, the CEO said. If it went to a conveyor system, that might prove more difficult.
"All of that is being looked at now," Soares said.
With the resource update, Foran also pegged inferred resources at 11.15 million tonnes grading 1.38% copper, 1.83% zinc, 0.10% lead, 0.47 g/t gold and 14.81 g/t silver. As in 2013, the latest resource was estimated using a net smelter return cutoff of US$60/t.
Foran raised C$9.4 million in mid-2018 to fund the McIlvenna project, including feasibility study work.