Many town of Greenfield residents wanted to pass regulations governing sand mines. But it was a gray area legally, because Greenfield, like many Wisconsin townships, is unzoned. That means anyone who owns land can use that land for whatever purpose they want. But one township in a situation similar to Greenfield's, the town of Cooks Valley in Chippewa County did enact a non-zoning ordinance regulating non-metallic mining--and sand mining is non-metallic mining. The property owner in the case challenged that ordinance, saying it was really zoning in disguise. A Chippewa County court ruled that the ordinance was invalid--but the Wisconsin Supreme Court ruled that that ordinance is indeed valid. This sets a huge precedent for townships across a state that is under siege by sand mines. It means that towns can adopt ordinances that require frack sand mining company to get a license to do so.
Here's link to a Wisconsin Municipal Law blog on the decision and another link to the Chippewa Herald's coverage of the case.