A sand mining company's bid to overturn the Winona County ban on frac sand mining has failed after the U.S. Supreme Court refused its case.

A lawsuit first filed by Minnesota Sands nearly four years ago sought to overturn the ban enacted in 2016, saying the moratorium was unconstitutional because it interfered with interstate commerce and violated the Constitution's commerce clause.

The ban was the first in the state to prohibit mining the rich silica sand deposits along the Mississippi River valley. The sand has tremendous value for the fracking industry. Silica sand is 95% quartz and consists of round, extremely hard granules that prop open cracks in shale rock, allowing the extraction of oil, gas and natural gas liquids. The ban allows mining for construction sand, a cheaper and less-pure material used on roadways .

Minnesota Sands first filed a lawsuit against the county in 2017. The Winona County District Court upheld the ban, as did the Minnesota Court of Appeals in a 2-1 decision in 2018. In March of last year, the seven-member state Supreme Court affirmed lower court rulings that let the ban stand, with two justices dissenting in full and one dissenting in part.

"The people of Winona County and throughout southeastern Minnesota have organized to oppose the frac sand industry for many years because this industry is incompatible with stewardship of the land and with healthy, thriving communities," read a statement from the Land Stewardship Project released Tuesday. The organization supported the ban's creation. "In passing the ban, the Winona County Board of Commissioners was fulfilling the proper role of local government, listening to the will of the people, and acting boldly to protect the common good for both people and the land."

Matt McKinney • 612-217-1747