Opponents may succeed in blocking plans for a proposed mining operation on the edge of Jordan after a yearslong battle.

The Scott County Board on Tuesday put a hold on the project amid concern over groundwater contamination, and county staffers wondered aloud whether the measures required to prevent pollution would be too expensive to be feasible.

"Anything's possible," environmental health manager Al Frechette said, but the two sides haven't been able to agree on a plan to monitor and mitigate that is both "economically feasible to fund" and acceptable to state and county officials.

The proposed gravel pit, lying on a flood plain and near several wells, would be rare if not unheard of in Minnesota. It isn't far from the flood-prone Sand Creek and the Minnesota River.

If polluted floodwater were to flow into the pit, it could seep into the groundwater.

"I am definitely concerned about groundwater contamination," County Commissioner Dave Menden said. Government agencies "spend millions preventing pollution, and this is so close to the aquifer. There's a lot of answers here that I don't have. No way do we want to think of getting close to polluting water we're trying to clear up."

County, city and township officials have been expressing concern about the project for at least three years. Some were asking for intensive environmental studies at least as early as January 2011.

The developer, Steve Hentges, could not be reached for comment.

An especially challenging twist to the issue, Frechette said, is the issue of how long monitoring would have to continue after mining ceases.

"When you add that in, it becomes very difficult," he said. People are talking about monitoring the effects of the proposed PolyMet copper-nickel mine in northeastern Minnesota for 500 years, he said. "That's a long time! How in the world do you arrive at what cost that entails? We'll have to have those discussions."

Kate Sedlacek, of Scott County Environmental Health, told commissioners that prolonged discussions did not produce agreement, so the local governments involved decided just to submit the developer's plan for comment, notably by state agencies. Both the Minnesota Pollution Control Agency and the state Department of Health found the plan submitted to be inadequate, she said.

The county's formal finding of inadequacy will now launch a process of further consultation, she said. County staff members have 60 days to prepare a plan that is adequate, working collaboratively with state agencies.

Jason Swenson, a water resources engineer with the county, said the main issue "is that this site is about two-thirds flood plain." Berming floodwater to keep it away from the site would just push it onto higher elevations and into the city of Jordan itself, he said, raising risks for others.

Citizen objections over the years have centered not only on water issues but also on dust and damage to roads. Trucks would use city streets that some say are not up to the abuse that legions of heavy vehicles would bring.

The proposed pit would be on about 80 acres, near the border between the city and Sand Creek Township, in the 17000 block of Valley View Drive, not far from Hwy. 169. After the mining is done, the pit would be turned into a pond.

David Peterson • 952-746-3285