On the coldest days on the Iron Range, Mike Sinko says mining dust rises in visible clouds. When the wind is right, the dust covers his deck and dirties his truck, even though he lives several miles from the nearest mine.

So the 61-year-old retired miner from Chisholm was skeptical but hoping for accurate information Monday, when University of Minnesota researchers detailed results of their long-term study examining links between mining dust and lung disease.

"I'm concerned," he said before the presentation started.

Dressed in a heavy coat and seated with other miners in the cold auditorium below the Hibbing Memorial ice arena, Sinko listened as the researchers detailed the research. Among their findings: For each year worked in the taconite industry, a miner faces a 3 percent increased chance of death from a type of lung cancer known as mesothelioma.

Using x-rays and medical exams, the researchers also found scarring in the pleural lining of the lungs for 16 percent of a sampling of miners — a sign of their exposure to harmful dust particles. But they did not find enough scarring in the lungs of spouses to suggest a broader exposure problem beyond the worksites.

Heavy coughs from the miners in attendance offered an audible reminder of the community's concerns. Some learned through the U research that they had abnormalities in their lungs and are at increased risk for mesothelioma.

"Thirty three-year employee," said Edward Alto. "Probably have a 100 percent [greater] chance?"

Then came preliminary results of an air quality study, which compared air purity around Iron Range mines, both operational and closed, against sample sites in the Boundary Waters Canoe Area Wilderness and atop a building at the U campus in Minneapolis.

Much to the surprise of Sinko and other miners, dirty air was more common at the U. Air quality around the mines was OK. "Some of the cleanest [air] in Minnesota," said George Hudek, a researcher with the U's Natural Resources Research Institute in Duluth.

That was a hard conclusion for Sinko to swallow, given the dust landing at his home. He left still skeptical.

"I don't buy that," he said.

Read the U's complete study of miner health and Iron Range contaminants at startribune.com