Konterra Magruder Surface Mine Reclamation Plan
The Konterra site is a 488-acre mixed-use, transit-oriented development with over 600 homes and a town center featuring upscale retail, shopping, and dining. Before this, the site known as the Magruder Surface Mine was the center for mining operations for 50+ years. At the time, the existing sand gravel mine had considerable backfill of construction debris that included asphalt, concrete, and trees. Soltesz worked with the landowners to prepare civil engineering support for a Voluntary Cleanup Program (VCP).
Soltesz prepared the mining reclamation plan including grading, sediment control, and stormwater management in accordance with Maryland state regulations. Our designs included four sediment basins, 100-year floodplain determination, dam breach analysis, a storm drain by-pass with a 78” RCP storm drain system, and coordination with the Maryland State Highway Administration for interface with the Inter-County Connector on the southern and western borders of the site.
This project was unique because of three main reasons: the sediment basin drainage areas ranged in size from 66 to 280 acres, their drainage areas were designed with concrete weir drop structures for three facilities, and a riser/barrel outfall structure for the fourth facility. The largest facility required approval from NRCS due to size, and also required the use of a slurry wall construction because the underlying fine sandy soils sloughed and prevented normal excavation techniques. The slurry wall surrounding the concrete drop structure allowed for this area to be dewatered and then excavated in a normal manner. All four facilities were converted to stormwater management facilities, with permanent pools ranging in size from 2.2 to 6.1 acres. Soltesz obtained approvals and permits from Prince George’s Soil Conservation District and the Maryland Department of the Environment Surface Mining Division for this VCP project.