County to pursue map of aggregate resources

Rock County is rich in aggregate materials, and county officials want to know where these resources are located and how to best manage the finite resource.
Commissioners adopted a resolution April 16 to work with the Minnesota Department of Natural Resources to map the sand and gravel potential throughout the county.
The county will devote $7,000 of in-kind services or contribute financially for the DNR’s Division of Lands and Minerals to begin the two-year study in July 2020.
Land Management Director Eric Hartman brought the mapping proposal to the board.
He said less than a quarter of the state’s 87 counties have gone through the mapping process, similar to the soil mapping the state has completed for decades.
“There are a number of areas in the state with a shortage of aggregate resources — even in our own region, and all we have to do is look over to the east end of Jackson and Nobles counties, ” Hartman said. “They have trouble finding decent aggregate resources for township roads.”
As part of the study, a DNR geologist will observe, complete bore samples, and designate all of Rock County land areas with limited, low, moderate or high aggregate potential.
Commissioner Stan Williamson hesitated in spending county funds to find out where sand and gravel resources are located.
“I see a little bit of the benefit,” Williamson said. “I am having a little trouble with seven grand.”
County administrator Kyle Oldre said aggregate mapping could help commissioners and the county’s planning and zoning committee make informed land permitting decisions.
“It would be good to know whether or not, at some point, you want to protect that (land) for future mining. Or at some point, maybe 100 years from now, we are going to run out of access to aggregate or not,” Oldre said.
Commissioners voted 4-0 to seek funding for the aggregate study through the DNR. Commissioner Sherri Thompson was absent.
Earlier this month, commissioners faced questions from the public relating to the number of open permits in an area and the effects of mining on the environment.
After lengthy discussions that included the company seeking the permits, the commissioners approved each of the conditional use requests.
Aggregate mapping is another valuation tool, similar to the maps designating the soil types on farmland throughout the county.
 “It’s (aggregate) another valuable resource we’ve got in this county,” Commissioner Gary Overgaard said. “It’s going to be worth a lot of money down the road.”
The DNR estimated more than 80 percent of publicly funded roads and infrastructure use some type of aggregate for construction and/or repairs.