Tierra Group performed a 3rd party engineering design peer review of a tailings storage facility expansion design. The review resulted in the owner realizing $650,000 in cost savings without compromising the facility's design integrity over the original design. Tierra Group also provided full-time construction quality assurance (CQA) for the tailings storage facility expansion. Tierra Group led a multi-discipline team to complete a scoping study evaluating tailings filtering for dry stack storage and use in underground paste backfill. Multiple dry stack layouts were completed and recommendations made based on construction costs and operational criteria. Results of the scoping study provided El Aguila mining engineers with necessary data for underground mine expansion planning. Tierra Group also provided Construction Quality Assurance (CQA) services during construction of a 70-m rockfill tailings dam.