Tag Archives: Iron Range

Teck forms 50:50 jv with Polymet as it targets production from Minnesota’s Iron Range

Teck Resources has announced an agreement with PolyMet Mining Corp to form a 50:50 joint venture to advance PolyMet’s NorthMet Project and Teck’s Mesaba mineral deposit, both located in the Iron Range of Minnesota, USA.

The joint venture will be named NewRange Copper Nickel LLC, with Glencore plc retaining its majority equity interest in PolyMet and providing financial support for its share of the funding commitment to the joint venture.

“The NewRange Copper Nickel joint venture brings together two large, well defined mineral resources in the established Iron Range mining region of Minnesota,” Don Lindsay, President and CEO of Teck, said. “This agreement will help unlock a new domestic supply of critical metals for the low-carbon transition through responsible mining.”

Closing of the transaction will be subject to customary closing conditions, including receipt of all required regulatory approvals.

The NorthMet project is near both existing and closed iron ore mines and utilises existing brownfield tailings storage and plant locations to minimise environmental impact. NorthMet is expected to produce 29,000 t/d of over a 20-year permitted mine life, with first production targeted for 2026. Over its first full five years of operations, NorthMet is expected to deliver annual payable production of 30,000 t of copper, 3,600 t of nickel, 58,000 oz of palladium, and 12,000 oz of platinum.

Earlier this year, the Minnesota Court of Appeals affirmed nearly all aspects of the water discharge permit for the NorthMet project, overruling six of the seven challenges to the permit made by mining opponents and paving the way for the “reactivation” of this key permit, PolyMet Mining Corp Chairman, President and CEO, Jon Cherry, said at the time.

The Mesaba mineral deposit, in the Duluth Complex near the NorthMet project, contains one of the world’s largest undeveloped copper-nickel resources, according to Teck. While further studies and community consultations are required to fully define the long-term development potential, Mesaba represents a strategic metal resource for North America, it added.

Twin Metals looks to avoid tailings dam concerns with dry stacking plan

The developer of the Twin Metals project, in the Iron Range region of northeast Minnesota, USA, has announced plans to use dry stacked tailings at the underground copper, nickel, platinum, palladium, gold and silver asset as the company looks to eliminate the perceived risk of a dam leakage or failure.

Twin Metals Minnesota (TMM), a company owned by Antofagasta, said the dry stack method eliminates the storage pond and dam associated with conventional tailings facilities and has been successfully used in four mines in the northern US and Canada with similar climates to Minnesota.

In 2018, an update of the prefeasibility study for Twin Metals outlined a 18,000 t/d ore project, producing an average of 42,000 t/y of copper, plus nickel and platinum group metals as by-products, the equivalent of some 65,000 t/y of copper.

TMM, like many other potential mine developers, said community concerns about copper-nickel mines have focused on fears of tailings dam failure or leaks that could threaten both nearby surface water and groundwater. This comes after several high profile dam failures in North and South America.

If all goes to plan, the company will use the dry stack method to store the leftover rock from its proposed underground mine on a lined ground facility near the plant site. This will allow reclamation of the tailing site to occur in stages, with the site capped or covered with natural vegetation.

Kelly Osborne, Chief Executive Officer of Twin Metals Minnesota, said: “Dry stack tailing storage is the most environmentally friendly tailings management approach for our site. The first key is that there’s no dam, no risk of dam failure. The moisture content of the filtered tailings is reduced to a material that we can compact and manage seasonally.

“Because there’s no risk of a dam failure, dry stack is considered the best available technology for tailings storage and, after a decade of study and consultation with concerned voices in our community, we determined that it will be an effective choice for our project.”

Equally important, TMM said, is the fact that the tailings from the Maturi deposit at Twin Metals will be non-acid-generating.

“The common concern about sulphides points to a basic misconception about our project,” Osborne said. “The geology of the Maturi deposit provides us with confidence that we can mine here safely and sustainably. The rock sandwiching the layer of copper, nickel and platinum group minerals in the deposit is almost completely free of sulphides. When the targeted minerals are removed during the concentration process and shipped to customers, only a minute amount of sulphides will remain in the tailings.”

Extensive testing over the past decade shows that Maturi deposit tailings will be non-acid-generating, the company clarified.

Dry stack tailings storage has been an option under consideration since Twin Metals began mine planning in 2010, the company said. “As technology has continued to advance, and the application of dry stack in cold, wet climates has proven successful at multiple locations, Twin Metals made the decision to move to it as the best available option,” TMM said, adding that The Minnesota Center for Environmental Advocacy hailed the advantages of dry stack tailings in a statement earlier this year.

Osborne concluded: “Dry stack is one of the ways we are making a 21st century mine that will be the most technologically advanced mine in Minnesota’s history and a model of how copper mining can be done safely and sustainably.”

The approach will be outlined in detail in TMM’s Mine Plan of Operation, to be submitted to state and federal regulators in the coming months. Regulatory review, including hearings for public comment, will cover compliance with regulations to protect water and air quality, drinking water, wetlands, endangered species, plant life and cultural resources. While the MPO is being reviewed the company will advance the feasibility study.

After reaffirming Twin Metal’s right to renew its two federal mineral leases, the Department of Interior reinstated the leases to TMM in May 2018. Antofagasta expects these to be renewed during 2019.