Commission approves Pentagon Materials’ 60-acre expansion and wet mining into water table with monitoring conditions

The Scott County Planning Advisory Commission approved an interim use permit amendment allowing Pentagon Materials to expand sand-and-gravel mining at the Schultz Bridal Pit in St. Lawrence Township from about 26 acres to 86 acres.

County principal planner Greg Wagner and Kirsten Pauley, a geologist and civil engineer with Sunday Engineering representing Pentagon Materials, told commissioners the expansion would add roughly 60 acres and allow deeper excavation into pockets of material 30 to 40 feet below the existing water table in places. Pauley said the existing interim use permit already allows mining into the water table by backhoe; the amendment would permit use of larger wet-mining equipment (for example a dragline or dredge-style bucket) where the resource extends deeper than the 20-foot practical limit of a backhoe.

Pauley described the environmental review and mitigation the applicant has in place. Because the expanded site exceeds 40 acres, the project triggered an Environmental Assessment Worksheet overseen by the Minnesota Environmental Quality Board process with Scott County acting as the regulatory government unit; the Scott County Board adopted findings of fact and a negative declaration on the need for an environmental impact statement in October 2024, Pauley said. County staff and the consultant described required and existing permits: a Minnesota Pollution Control Agency air permit (including fugitive dust controls), an NPDES stormwater permit, a Department of Natural Resources water-appropriations permit for the wash plant, annual solid-waste licensing for on-site concrete and asphalt recycling, and a quarterly groundwater monitoring program for diesel-range organics and nitrates.

Commissioners and public commenters asked about groundwater, monitoring and nearby wells. Pauley said a network of monitoring wells exists in the mining corridor — including wells at nearby Valley Paving and the Miranda mine — and that monitoring at the Schultz site itself will continue, with samples taken three times per year and submitted to an independent lab. She explained wet-mining removal uses a bucket to lift saturated material, the water drains back to the excavated area by gravity, and the operation does not introduce chemicals into the groundwater.

Project operations would use County Road 66 as the primary haul route to State Highway 169. Wagner said the operation anticipates a 20–25 year life of mine and includes phased reclamation to return the site to agricultural condition; a permanent water feature of roughly 2.5 acres and about 20 feet deep is included in the reclamation concept as a stormwater/outflow and aesthetic feature. Reclamation would place granular material below the water table and organics/clay in the upper ~3 feet to support future agricultural use, the consultant said.

The commission held a public hearing with questions from Louisville Township officials and other attendees. After closing the hearing, Commissioner Huber moved to recommend approval of the interim use permit amendment, Commissioner Robinson seconded, and the commission voted to approve the amendment. Staff noted conditions and required permits must be met before final Board consideration and ongoing monitoring and permit compliance will be enforced.