Sweetwater Mine Permitting

Tierra Group’s Team began work at the Sweetwater mine in 1993 assisting permitting and developing tailings impoundment management strategies for the mine. We successfully designed and installed an innovative internal seal for repair of the mine’s damaged decant discharge conduit. Tierra Group began working at Sweetwater again in 2015 designing a 5 foot TSF dam and spillway raise. Unique design challenges were overcome with a comprehensive field investigation including CPT and hollow stem auger drilling. Liquefaction analyses were performed and incorporated into the upstream raise design. A challenging hydrology model was completed and a raise to the existing spillway was designed. The raise design was approved by MDNR Dam and Reservoir Safety council in March 2016. Construction was completed in early 2017 with support provided with Tierra Group overseeing construction activities and evaluating proposed design changes. An As-Built report was completed in April 2017 conforming to MDNR requirements. Tierra Group provided additional support at Sweetwater by developing a deposition plan, water balance, hydrology study, and geotechnical modeling to design an additional tailings dam raise.