The number of Wisconsin frac sand mining operations has more than doubled in the past year, the Wisconsin Center for Investigative Journalism found, and the state leads the nation in production.
                 
A year ago, the Center identified 41 facilities operating or proposed in the state. The La Crosse Tribune reports there are 87 are operating or under construction this summer, with another 20 facilities in the proposal stage.

The frac sand boom has divided residents into those who believe mining will create sorely needed jobs in rural Wisconsin and those who fear the impacts these mines may have on human health, road safety and the environment.

Some communities have readily welcomed frac sand mining for economic reasons. Others, including Buffalo, Dunn, Eau Claire and Pepin counties and a handful of towns, slapped on temporary moratoriums to give them time to review and update their land-use regulations.

The demand for sand has soared in tandem with the explosion in controversial hydraulic fracturing operations across the country. The sand is used to prop open fractures in the bedrock, allowing oil or natural gas to flow past.