How much sand could feasibly be harvested in Winona County for oil and gas "fracking" and other industries? According to information recently provided to the Winona County Comprehensive Plan Advisory Committee, nearly 25,000 acres of silica sand are close enough to the surface to be economically viable for mining in Winona County. Another 218,000 acres of Jordan Formation sand rests further below, unlikely to be excavated because of the expense and environmental consequences of digging that deep.
Sandstone located in the St. Peter and Jordan formations is, for the most part, the type of sand sought by the hydraulic fracturing industry, said Winona County Planning and Environmental Services Director Jason Gilman. Over 16,000 acres of St. Peter sand is considered viable for mining, and just over 8,000 acres of Jordan Formation sandstone is close enough to the surface to be removed. Gilman said much of the Jordan sand that is close to the surface is found in valleys throughout the county.
Gilman cautioned that not every bit of sand that is generally closer to the surface would be easily extracted; some would be difficult to remove, and some is of lower quality than is acceptable for the hydraulic fracturing industry. For that process, the sand must be able to withstand high pressure and not break, because it is used to hold open fissures in shale rock formations while oil or gas is extracted.
The deeper Jordan Formation sand — 218,000 acres — would be very expensive to mine, said Gilman, unless an existing quarry or other land use has already removed much of the upper layers of rock. That is the case for Biesanz Quarry, which has extracted Jordan Formation from the lower parts of the quarry that have been excavated over the last 100 years. Some companies have extracted Jordan Formation sand that is at so deep below the surface by excavating into the side of bluffs or ridges from the valley floors, Gilman noted.
The map provided to the Comprehensive Plan Committee showing the acres that could possibly be mined does not account for areas that would not be feasible for mining because of floodplain, wetlands, or other zoning restrictions. This year, the Minnesota Legislature passed a provision that requires any new sand mine to be located within one mile of a trout stream to receive a permit from the Department of Natural Resources in order to operate. The map accounts for acres that are near trout streams, said Gilman, because it is still possible to mine those areas as long as a permit is secured.
Examining the future of the sand mining industry is one of many topics under review by the Comprehensive Plan Committee. The group is tasked with drafting a new Comprehensive Plan, a document that is used as a framework for regulations and land use decisions. The plan includes community goals and values, as well as expectations and guidance for industries from farming to tourism. The committee is currently working on a plan to gather public input and township ideas. The next committee meeting is scheduled for Monday, September 16, at 7 p.m. at the county office building on Main Street.