Toronto-based Duluth Metals (DM-T) and 40% joint-venture partner Antofagasta (ANTO-L) can claim to hold one of the largest pollymetallic sulphide deposits following a resource update on the Twin Metals project near Ely, Minn. Duluth announced the resource estimate earlier this month, which grows the project’s in-situ copper-nickel numbers and establishes one of the largest palladium-platinum deposits outside of South Africa.
Lying along the South Kawishiwi intrusion in northeastern Minnesota, the Twin Metals resource runs over three deposits, including: Birch Lake, Maturi and Spruce Road. The Twin Metals partnership has been working to achieve clarity on continuous zones of higher-grade mineralization for an upcoming prefeasibility study that should put the project another leg down the road to production.
Duluth’s resource for Maturi covers 405,000 metres of drilling and holds 907 million indicated tonnes grading 0.59% copper, 0.19% nickel and 0.6 gram per tonne platinum-palladium-gold (3PE), as well as 491 million inferred tonnes averaging 0.51% copper, 0.17% nickel and 0.53 gram 3PE.
Based on 90,500 metres of drilling, the Birch Lake deposit holds 89 million indicated tonnes grading 0.52% copper, 0.16% nickel and 0.86 gram 3PE, as well as 216 million inferred tonnes averaging 0.46% copper, 0.15% nickel and 0.64 gram 3PE.
Spruce Road relies on data from 210 legacy holes, and as such the resource remains in the inferred category. The deposit hosts 435 million tonnes grading 0.43% copper and 0.16% nickel. All resources rely on a 0.3% copper cut-off.
When taken as a whole, the three deposits hold indicated contained metals totalling 13.7 billion lb. copper, 4.4 billion lb. nickel, 5.6 million million oz. platinum, 12.6 million oz. palladium and 3 million oz. gold.
Duluth highlights a higher-grade core to the Maturi deposit that could offer higher returns during early production. Labelled S3, the Maturi subunit hosts 564 million tonnes grading 0.69% copper, 0.22% nickel and 0.76 ppm 3PE in the indicated category and 180 million tonnes grading 0.65% copper, 0.21% nickel and 0.82 ppm 3PE in the inferred category. S3’s resources are at a higher cut-off grade of 0.5% copper.
“The [final report] confirms the impressive nature of the deposits,” Duluth president Vern Baker says. “All key parameters including grade, tonnage and contained metal have grown substantially. Mine planning will focus on using the higher-grade areas for initial mine sequencing, potentially improving the business-economic model.”
Duluth has traded within a 52-week range of $1.39 and $2.76. The company has 125 million shares outstanding and closed at $2.48 at press time with a $311-million market capitalization. The company reported US$17 million in cash as of Nov. 2, with funding for the first two phases of its joint venture complete.
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