A small frac sand mine first proposed in October 2011 won approval by Winona County Tuesday despite persistent opposition from local residents who fear it could pave the way for a cluster of other sand mines in the area.

The 19-acre David Nisbit mine in rural Saratoga Township will become the eighth or ninth commercially producing frac sand mine in Minnesota, and only the second such pit in Winona County. It will dig and haul silica sand at a rate of up to 140 semi-truck loads a day.

The County Board approved the proposal on a 3-2 vote, but the mine’s operating permit will contain at least 40 conditions, ranging from spill protections to local road-use payments, said Jason Gilman, the county’s planning director. Gilman said it’s not clear when mining will start, but he said the operators are anxious to complete a final round of administrative requirements.

Gilman said the review was delayed last year by a citizen-generated moratorium and a subsequent debate over how intensely the county should study environmental effects of the proposed mine.

The County Board approved a level of review that certain residents opposed as too shallow, and a dozen of those residents are still appealing the board’s decision in court.

Vince Ready, a farmer in Saratoga Township who opposed the mine, said activists once again packed Tuesday’s board meeting, only to see another decision go against them. “We are always run over by the well-monied mining interests,” he said.

Local opponents of the industry fear that their pastoral township — home to a considerable Amish population — will become a hub of frac sand mining if several other proposed sites in the area are developed, Ready said. Some of their concerns were echoed earlier this year by the state Pollution Control Agency and Health Department, which called for a study of potential environmental and health consequences that could result from cumulative mining operations in the area.

In response, a frac sand group with prominent mining proposals for Winona County and neighboring Fillmore County has volunteered to conduct such a study.