![]() There are no standards for fibers in the air, either on the national level or in Minnesota. Paul.īut some people worry even that level could make people sick. But at monitoring stations about a mile away, the numbers drop to a level comparable to the city of St. Millions of fibers pour from the smokestacks. NorthShore Mining Company currently operates the former Reserve mine and processing plant. "Whether or not this has any significance in terms of human exposure as you get further and further away from the source, it's questionable," he adds.Ĭook says the way to assess the risk to humans is to nail down how many fibers it takes to cause cancer, and then find out how many fibers are in the air. David Trach, retired steelworker, on the importance of screening for lung abnormalities They're in their 60s and 70s, and can hardly breathe. We've got to search out for those young miners that are working now, so they don't end up like some of my friends did at LTV Steel. "You could see very clear signatures of magnetite from the taconite industry, and I can't tell you from memory right now how far that was, but certainly 20 miles away you could find a trace."Ĭook says that means in principle the taconite dust can be transported large distances. So the number of fibers were increasing and the dose was increasing."Ĭook says the very thin, short particles in the taconite fibers caused more cancer than the longer fibers typical of asbestos.īut one of the outstanding questions is: are people who live near the mine exposed to enough fibers to worry about cancer?įor two winters, Phil Cook and his colleagues collected dust from the snow at various locations between the mine and Duluth. "Blocky particles would become thinner fibers. "So there was some kind of slow leaching going on while the fibers were in tissue," Cook says. The taconite fibers had actually multiplied during their two years in the rats' lungs. He then used an electron microscope to count the fibers still in the lung tissues. After two years, the taconite fibers had produced at least as much cancer as the asbestos, and in some cases more. He injected a carefully controlled number of each type into rats' lungs. He compared the fibers in taconite with asbestos fibers, which are known to cause cancer. He conducted animal studies to see how likely the fibers were to cause cancer. "Hundreds of hours of looking at many fields of view, and counting particles of all sizes and shapes, and identifying them specifically as to what their mineral nature was."Ĭook has been asked to bring his research to the conference. "I had people working with me who did an excellent job on the electron microscope," he says. Cook and his team pioneered use of the electron microscope to get a handle on the fibers. The fibers are so small, you can't see them even with a regular microscope. ![]() He's a chemist at the National Water Quality Lab in Duluth. Phil Cook is one of the people who discovered the fibers in the water supply. Reserve was forced to dump its waste rock on land.īut the jury is still out on whether the fibers are dangerous. People panicked and started drinking bottled water, until a special filtration plant was built. Reserve Mining Company was dumping its waste rock in Lake Superior, and taconite fibers turned up in Duluth's drinking water. The fibers in taconite first made big news thirty years ago. The answer could have a big impact on future mining projects, and the economy of northeastern Minnesota. Organizers of this week's conference will try to determine once and for all whether taconite fibers pose a health risk. Some studies show the fibers in taconite cause cancer too. Those microscopic fibers are a lot like asbestos, and asbestos causes cancer. Paul to talk about the possible dangers in fibers in taconite ore. Researchers from around the world are gathering in St. Questions remain about whether taconite fibers pose a human health risk. ![]() Waste rock is deposited on land a few miles from Lake Superior. NorthShore Mining Company now operates the former Reserve mine and taconite plant. Join the conversation with other MPR listeners in the News Forum.īy Stephanie Hemphill, Minnesota Public Radio
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