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NRRI: At the forefront of mining innovation
Photo: Nine engineers and 22 lab technicians work at NRRI’s Coleraine Minerals Lab. Researchers are working on a variety of mining projects, including lean ore recovery and ways to process copper without an autoclave. Photo by Beth Bily
The innovation, challenges and opportunities faced by the mining industry will be at the forefront of discussion at this month’s Society for Mining, Metallurgy and Exploration (SME) conference in Duluth.
That’s nothing new for engineers and researchers at the Natural Resources Research Institute (NRRI) Coleraine Minerals Lab. Here, nine engineers and 22 lab technicians, all trained in mining and minerals processing, tackle mining’s challenges and new opportunities every day.
The facilities are unique, said Director Richard Kiesel. The lab is one of only four in the world. While its primary focus is to support Northeastern Minnesota mining operations, it also handles projects from around the world.
The lab takes projects from the engineering and design stage to bench scale and ultimately pilot scale testing. Research plays a critical role for existing mining companies looking to innovate their processes as well as upstarts that hope to get a new company off the ground.
“A lot of banks require successful pilot tests for financing,” Kiesel said. “The mines have let us become their screening operation.”
NRRI has contracts in place with nearly all the mining companies operating regionally. Here, they test new mining methods and technologies.
Kiesel reports that one current effort focuses on lean ore recovery, or mining magnetite and hematite from existing waste piles. The methodology is similar, but not identical, to that used by Magnetation, which mines tailings basins on the western Mesabi Range.
“We’re working toward technology that could open the door to even more companies” entering the lean ore recovery business, said Kiesel.
The minerals lab also is focused on diversification efforts. The industry is changing due to reductions in the number of blast furnaces in operation and an increase in mini mills, which require higher-quality feed stock than the traditional taconite pellet.
Mini mills offer a number of potential benefits including lower capital costs and an easier path to permitting. Mini mills have traditionally utilized scrap metal, but quality scrap is becoming a scarce commodity, creating a need for alternatives, such as the high-grade iron nuggets produced by Mesabi Nugget on the East Range.
In recent years, the push toward diversification has included the potential from mining metals other than iron. There are several projects in northeastern Minnesota that propose to mine copper, nickel and other precious metals. PolyMet is the furthest along in the regulatory review process.
PolyMet is proposing a copper/nickel operation that would process minerals using an autoclave. NRRI researchers, however, are looking at ways to process copper that doesn’t use one. “The technology looks promising,” said Kiesel.
NRRI scientists also are researching ways to mitigate the negative environmental impacts of nonferrous mining. Several environmental groups have voiced opposition to mining precious metals in the Duluth Complex. Copper, nickel and other metals are bound with sulfides, which when mixed with air and water can result in sulfuric acid.
Local tribes also have voiced opposition to nonferrous mining. Tribal leaders say wild rice producing rivers already have been damaged by the release of higher levels of sulfate from iron mining – an issue they believe would be exacerbated if nonferrous mining also took place. The issue arises when sulfates leach into soils and waterways from tailings basins.
David Hendrickson, NRRI director of strategic development, is leading a research effort that uses natural methods to greatly reduce sulfates near sensitive wild rice producing areas.
There is currently some doubt about what sulfate levels may be allowable under law. Federal Environmental Protection Agency regulations allow 250 parts per million in drinking water. However,
Minnesota regulations call for only 10 ppm, a regulation that hasn’t been enforced, said Hendrickson.
“If 10 ppm is enforced, that’s a concern for (iron) mining companies and for copper/nickel operations,” he said.
Hendrickson and other researchers already have created floating bio-reactors that contain sulfate-reducing bacteria.
Made from recycled materials, the bioreactors can be placed near tailings basins, which although lined, still seep sulfates into nearby soils and waters often at levels of 1,000 to 1,500 ppm.
Pilot tests on Cliffs’ Erie property show the technology can reduce sulfate levels significantly. The treated waters could then be further refined with reverse osmosis polishing systems to bring sulfate levels to 10 ppm.
Hendrickson hopes to take his research even further. He’s applied for grant funding though the National Science Foundation and the University of Minnesota MnDRIVE grant program. He’s also requested a second round of funding from the University of Minnesota Duluth and Iron Range Resources and Rehabilitation, which collectively funded the first round of his research.
The first testing, he said, demonstrated that chemistry targets could be successfully met. Second round testing will increase water flow rates.
Hendrickson’s research, like other research conducted by the NRRI, isn’t science for the sake of science. The application of this technology, if successful, could translate into a healthier economy in northern Minnesota.
“Nobody wants to see mining jobs lost over this” sulfate issue, he said.Previous BusinessNorth Exclusives Articles:
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