WINONA, Minn. (AP) — A judge has dismissed a challenge to Winona County's ban on industrial frack sand mining.

Minnesota Sands, a company with leases on thousands of acres in southeastern Minnesota, along with a group of landowners sued the county. The landowners contend the 2016 ordinance violates their rights by singling out sand used for industrial purposes while permitting mining of sand for construction.

Winona County Judge Mary Leahy dismissed the claims on Friday. The Winona Daily News reports Leahy ruled the county board acted within its authority.

Silica sand is used in hydraulic fracturing, or fracking, a drilling process used to unlock underground oil and natural gas reserves.

Demand for frack sand led to a boom in mines across western Wisconsin and southeastern Minnesota, although demand later waned with falling oil prices.