Frac Sand Fever is an occasional series by Star Tribune reporters on the sand-mining boom that has developed in Minnesota and Wisconsin, as "hydro-fracking'' revolutionizes the nation's oil and gas industry.

Sept. 30: A $55 million sand processing plant could make tiny St. Charles the gateway to a new mining frontier in southern Minnesota.

Oct. 28: Mining companies are hiring away county engineers and regulators, raising ethics questions and leaving communities short-staffed in the midst of a burgeoning land rush.

Today: The sand boom is creating sudden wealth -- and new tensions -- for families in Wisconsin and Minnesota whose land is coveted for fracking.