Tom Rowekamp shows some grains of silica sand that were extracted from the Nisbit mine, Nov. 7, 2013. Alex Kolyer | For MPR News 2013

Houston County commissioners have voted against a ban on silica sand mining, disappointing its opponents.

The ordinance would have made the county in far southeastern Minnesota the first in the state to ban the practice. Fillmore, Winona and Wabasha counties have passed rules restricting silica sand mining in recent years.

When Houston County's moratorium on silica sand mining expires on Thursday, the rules will revert to the existing ordinance which does not specifically mention silica sand, Deputy County Auditor Michelle Quinn said.

Silica sand is used in a natural gas extraction process called hydraulic fracturing, or fracking. When the sand is forced into underground rock formations it breaks up the stone, releasing large amounts of natural gas. The hard Minnesota sand is perfect for fracking, because it can withstand the intense pressure needed to break rock.

Critics of sand mining say an all-out prohibition would have been a victory for many who have fought to keep the industry out of the county.

"We're pretty upset about what the county board didn't do," said Ken Tschumper of La Crescent. "The end result is we're right back where we are with our current zoning ordinance."

There are currently no silica sand mines in Houston County but county officials say it is home to nine active mines used either for construction or agricultural purposes.