WINONA — A sand mining company has agreed to a voluntary environmental review of two mines it’s proposing for Winona County.

Winona County officials had planned a hearing Thursday night on whether to require an environmental impact statement on the proposals. The hearing was canceled after Minnesota Sands agreed to the voluntary review.

The more-detailed review isn’t required by state law, so it had been up to Winona County officials to decide whether to require one.

The decision by Minnesota Sands comes two weeks after the Minnesota Department of Health and Minnesota Pollution Control Agency called for an environmental impact statement on the proposals.

Demand for silica sand is high because it’s used in hydraulic fracturing, or “fracking,” that produces oil and gas.