Sand has become a valuable – and deeply divisive – commodity in the upper Midwest. Hydraulic fracturing, a method of extraction also known as fracking that has boosted oil and natural gas production across the United States, requires sand, and there's plenty of it here.
And so in dozens of small towns and rural townships in Minnesota, Illinois, Iowa and especially Wisconsin, the demand for frac sand, as it's called, has brought a surge of new mining activity. Scores of companies have poured in, eager to take advantage of the thick sandstone that underlies the bluffs and ridges of the region's picturesque river country.