Published by The Heartland Institute. As many as 9,000 non-metallic mines operate in Illinois, Iowa, Minnesota, and Wisconsin – approximately one mine for every 3,000 residents. Until recently, those mines have operated without opposition. But industrial sand mining recently has become a more contentious issue as environmental groups have taken note of the growing number of mines meeting the growing demand for the industrial silica sand used in oil and natural gas development, referred to as “frac sand.” In this Policy Study, the third in a series addressing frac sand mining topics, the authors specifically address the potential impacts of frac sand mining on public roadways.