Ely copper deposit estimate doubles

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Already reported as the world’s largest untapped deposit of copper, the Twin Metals mine exploration area near Ely contains even more copper, nickel, platinum and other valuable metals than previously estimated, the mine’s parent company said Wednesday.

Toronto-based Duluth Metals released an updated resource estimate that’s double its 2009 estimate, though the new findings aren’t likely to change the already developing plans for Twin Metals mining operations.

Data gathered from exploratory drill sites, including 170 new drill core samples reviewed in the past nine months, indicate a staggering 8 billion pounds of copper, 2.5 billion pounds of nickel and 12 million ounces of palladium, platinum and gold underground at the site along Highway 1 near the Kawishiwi River.

Tests indicate an “inferred” but not yet proven estimate of up to 13.5 billion pounds of copper,

4.6 billion pounds of nickel and 15.8 million ounces of palladium, platinum and gold. Company officials said Wednesday the deposit could hold more than $100 billion worth of the ore.

The company has analyzed thousands of feet of drill-core samples taken from more than 650 old and new drilling sites across the Twin Metals exploration area, which covers about 32,000 acres the company has access to. And the company reported strong signs of major deposits just outside its current proposed mine, areas for future expansion.

“It’s big news. But it’s not surprising,” said Bob McFarlin, Twin Metals vice president of public and government affairs. “It’s (Wednesday’s report) part of the project development process. It’s an affirmation of the fact that we are talking about (a copper-nickel-platinum) deposit of world-class magnitude.’’

McFarlin said among the most interesting aspects of the new report is the scale of copper-nickel-gold deposits now confirmed. It’s the added value of those precious metals that give the Twin Metals project a huge financial boost, he noted.

While Wednesday’s was the most recent formal update of the value of the underground resources, most Northlanders who have followed the project already have seen its expanding scope. Just last month, Duluth Metals reported that there is so much copper in between their Nokomis and Maturi proposed mine sites that they would merge the two deposits under the Maturi name.

It’s not uncommon for proposed mines to upgrade their estimates for the value of resources in the ground, especially as analyses of hundreds of drill core samples come back positive. The updates are required by Canadian law of Canadian mining companies to keep investors accurately abreast of what so-called Canadian Junior mining companies are finding at their project sites.

The expanded numbers already were known by Duluth Metals in March when the company formally announced that it had instructed its engineering contractor, global giant Bechtel, to draw up plans for an up to 80,000-ton-per-day mine and processing plant. That size mine would put Twin Metals on par with the largest mines in the world. It would be among Minnesota’s first copper mines and would be the largest underground mine ever in the state.

The Twin Metals project is expected to cost up to $3 billion, one of the state’s largest private enterprises of all times, and could employ more than 1,000 people to mine about 400 million tons of ore-bearing rock. By comparison, PolyMet Corp. is proposing a $600 million open-pit mine and concentrating center, employing about 350 people while processing about 32,000 tons of copper and other metals a day for about 20 years or more.

Duluth Metals officials say that, depending how fast the company decides to mine, there’s enough ore to last a half-century or more. The mine will be so big, with miles of tunnels reaching about 4,500 feet below ground (and potentially below Birch Lake), that giant dump trucks will simply drive right down a gradual decline to the ore. Some of the processing may even happen deep in the mine, and much of the leftover rock will be back-filled into the mine.

Canada-based Duluth Metals owns 60 percent of the Twin Metals project, and Chilean-based Antofagasta owns the other 40 percent.

Betsy Daub, policy director for the Friends of the Boundary Waters Wilderness, said Wednesday’s announcement is “a call for Minnesotans to learn more about sulfide mining and what it could mean for this region, and weigh in on whether right next door to the Boundary Waters is the right location for something like this.”

No mine of this type has ever managed to avoid polluting nearby waters, Daub said, adding that the record around the world shows they fail to deliver promised economic benefits.

The mining industry insists that modern technology can put Minnesota on the forefront of mining these minerals in an environmentally responsible way.

The Associated Press contributed to this report.

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