From an article by Molly Newman in the Marshfield News Herald:

Three companies have their sights set on excavating a high quality sand that lies about 20 feet below Marshfield’s surface.

The hard, round sand, called frac, is found only in older deposits in certain areas, including central Wisconsin. It’s used in hydraulic fracturing, or breaking apart rock using sand and water to pump out oil and natural gas.

Several companies have popped up in the area recently because of increased interest from the oil industry, Completion Industrial Minerals President Tom Giordani said.

“There are shortages in the market for the sand — that’s why everyone’s looking in Wisconsin,” he said.

Completion, formerly TexSand, had some funding delay its business plan during the recession, but now is back on track to begin excavation this summer, Giordani said.

The company is in the process of grading its 57-acre site on 29th Street in Marshfield’s Yellowstone Industrial Park and setting up the excavating equipment, including crushers, screens, dryers and belt conveyors. There will be some small control buildings and two 100-foot storage silos on the site, with an office building constructed later, Giordani said.

Some sand excavation is expected to begin in August and the system will be fully operational by September or October, he said. There is enough sand in the Marshfield area pits Completion is using to last at least 25 years, he said.

But it’s been a contentious issue in some states that have fracking operations. Critics argue that chemicals used in fracking may be contaminating water supplies. And it’s the subject of a documentary titled Gasland.