A huge copper-nickel mine proposed for just south of the Boundary Waters Canoe Area has again increased the estimate of minerals at the site.
Twin Metals is one of several companies exploring for copper, nickel and precious metals in the Duluth complex in northern Minnesota. The area is believed to be the richest untapped deposit of these minerals in the world.
Twin Metals is the second furthest along in developing a mine proposal, after PolyMet. This new report shows a 19 percent increase in estimated minerals compared to its last filing in June, said Bob McFarlin, Twin Metals' vice president of public and government affairs.
"The pattern is the same, and that is, that Minnesota's resource, the more we learn about it, the greater the magnitude," he said.
The deposit is enough to mine for over a century, McFarlin said.
"The mineral resource of Minnesota for copper, nickel, platinum, palladium and gold, these strategic metals, is of world-class magnitude, and just presents a tremendous economic opportunity for the state," he said.
It will take Twin Metals another year or two to develop a mine plan of operation to present to state and federal regulators, McFarlin said. That will then trigger the environmental review process.
It takes a typical mining project of this scope in the U.S. seven to 10 years to conduct project development studies and go through the environmental review and permitting process, according to McFarlin. Twin Metals launched its "prefeasability study" in October, 2011.
Twin Metals is co-owned by Toronto-based Duluth Metals and the Chilean mining giant Antofagasta.
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