MOUNTAIN IRON — Taconite industry workers face an increased risk of contracting a rare form of lung cancer and the risk increases the longer they remain on the job, University of Minnesota researchers announced Friday, but said they can’t say for certain if dust from the state’s iron mining and processing operations causes it.

The researchers traveled to the Iron Range of northeastern Minnesota to announce the findings of their $4.9 million, five-year study into possible links between taconite dust and mesothelioma, a rare cancer of the lung lining caused by exposure to airborne asbestos fibers that has taken the lives of 82 taconite workers over the years.

Previously released research confirmed a 300 percent higher rate of mesothelioma on the Range than the general population in Minnesota.

“Our goal was to begin answering questions around how mining and taconite processing have impacted the health of Minnesotans. These studies have started to uncover those answers,” John Finnegan, dean of the university’s School of Public Health, said in a statement.

Asbestos fibers fall into a family of “elongated mineral particles” that are present within dust from taconite operations. Taconite, a low grade of iron ore, can contain asbestos. But the types of EMPs generated by iron mining had not previously been linked to an increased risk of mesothelioma.