Tierra Group was commissioned by Doe Run to design a new tailings storage facility at the Brushy Creek Mine. Tierra Group completed a geotechnical investigation including boring, classifying, and sampling soil and rock. Trade-off studies were performed to minimize construction costs. These trade-offs included construction material optimization through seepage modeling and spillway construction optimization through hydrology and hydraulic modeling. Seepage and slope stability modeling was also performed. A design report was submitted to Missouri Department of Dam Safety allowing Doe Run to obtain necessary construction and operating permits.