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In a critical test of Minnesota's approach to frac sand mining, two state agencies have called on Winona County to order an in-depth study of environmental and health risks associated with a cluster of proposed mines and processing sites.

The commissioners of the Minnesota Pollution Control Agency (MPCA) and the Minnesota Department of Health each published formal comments this week strongly urging the county to require a full environmental impact statement before deciding whether to approve at least two silica sand mines proposed by Minnesota Sands LLC. The Winona County Board will have final say on the study.

It's the first time either state agency has called for such an in-depth, precautionary study of frac sand operations, which have been booming in southeast Minnesota and western Wisconsin as firms demand the sand suitable for new drilling techniques that have revitalized the U.S. oil industry. The industry has created concerns as well as jobs, with two MPCA commissioners noting possible contamination of drinking water, lung disease and unsafe truck traffic.

"We want to understand the impact on our land, air and water," Commissioner John Linc Stine said in an interview. "It's a pretty strong recommendation from our agency, yes."

Winona County Attorney Karin Sonneman said her office will scrutinize the comments as it considers the county's options. In addition to health and environmental concerns, there are economic interests to balance, she said. The kind of extensive environmental review urged by state regulators is uncommon, costly and time consuming.

"This is one of the most significant things to hit Minnesota for a long time, so we are looking at this very closely," Sonneman said. "It's very important to our citizens and statewide."

The letter by Health Commissioner Dr. Edward Ehlinger discussed the area's unique geology and the way that drinking water supplies there are especially prone to infiltration of contaminants. Mining operations would remove the natural cover material that acts as a filter for the aquifer, he said, and plans for backfilling and reclamation would leave less cover.

Ehlinger also said Minnesota has "little to no information" on the levels of respirable silica generated by frac sand mining or processing. He said the toxicity of crystalline silica to humans has been well documented in occupational settings, with studies showing it can cause a number of lung diseases, including silicosis. He said his agency is developing exposure limits for dangerous particles in the air outside sand facilities and that current air monitoring projects could prove useful to assessing potential risks posed by proposed sand facilities in Minnesota.

Public hearing

Central to the debate is whether the proposed Dabelstein and Yoder mines in rural Winona County should be considered "connected" to at least three other proposed frac sand facilities within a 5-mile radius, including sites in Fillmore County. The cluster could also include a major processing and rail load-out facility near St. Charles. A group of investors is pushing that project, but the group hasn't formally applied for a permit.

Under state law, an in-depth environmental review is required for industrial projects if they are phased together in a certain magnitude. Stine and Ehlinger said in their letters to Winona County that an analysis of the various projects as connected actions would provide the most comprehensive and accurate assessment of potential effects.

Stine said the environmental data already submitted by Minnesota Sands do not address "to any significant degree" the potential, cumulative effects of the neighboring sites. In fact, he said, the company's disclosures "led to more questions than answers."

Winona County Administrator Duane Hebert said the next step is for the County Board and the county's planning commission to hold a joint public hearing Feb. 21 for more comment. By early March, the planning commission will issue a recommendation to the County Board.

"I don't think anything of this magnitude has come around for quite some time," Hebert said.

Tony Kennedy 612-673-4213