Tierra Group engineers designed La Esperanza TSF, a 2.1-km long, 35-m high, earthfill tailings dam with an HDPE lined impoundment footprint of 840,000 m2. Tierra Group designed and provided Construction Quality Assurance (CQA) for all subsequent downstream dam stages. Stage 6 and 7 dam crest raise designs incorporated mechanically stabilized earth (MSE) methods to maintain the facility within property boundaries, and reduce construction costs. Tierra Group also developed the detailed closure design for the Esperanza TSF. 

Tierra Group serves as the Engineer of Record (EoR) for the Esperanza TSF. As the EoR, Tierra Group conducted TSF dam breach and downstream inundation analyses, developed detailed TSF water balance, reviewed monthly monitoring data, conducted annual TSF inspections, and prepared an annual monitoring report to document TSF performance and dam safety.

Crimea In-Pit Tailings Storage Facility (TSF)

Tierra Group developed the Crimea In-Pit TSF Operations, Maintenance, and Surveillance (OMS) Manual and Emergency Action Plan (EAP). for the Crimea In-Pit TSF.

La Esperanza Tailings Storage Facility (TSF)

Tierra Group updated the La Esperanza TSF Operations, Maintenance, and Surveillance (OMS) Manual and Emergency Action Plan (EAP). for the La Esperanza TSF.

Crimea In-Pit Tailings Storage Facility (TSF) Phase 2 Geotechnical Investigation

Tierra Group completed a geotechnical field investigation to support the Crimea TSF Phase 2 design. Field investigation included exploratory borings, trenches, and laboratory testing on dam foundation materials and proposed borrow sources.

Aquifer Testing

Tierra Group installed and tested a series of wells around an existing pit to determine the feasibility of using the pit as a TSF. The aquifer testing on six wells consisted of constant rate drawdown tests to determine aquifer characteristics and boundary conditions. The test results were used to develop a 3D finite element model, including particle tracking and solute transport.

Conformance Audit Support

Tierra Group assisted with completing internal assessments to ensure the La Libertad and El Limon Tailings Storage Facilities (TSFs) conform to the Global Industry Standard on Tailings Management (GISTM) requirements. The GISTM has six topic areas encompassing 15 principles and 77 individual requirements. The conformance assessment follows the International Council on Mining and Metals (ICMM) guidance in “Conformance Protocols – Global Industry Standard on Tailings Management.”

Rosario & Tranca Open Pit Feasiblity Investigation

Tierra Group performed a geotechnical field investigation to characterize the geologic conditions and determine preliminary pit slopes for two proposed pits.

Crimea In-Pit Tailings Storage Evaluation/Design

Tierra Group evaluated the Tajo Crimea Pit’s geotechnical and hydrogeological characteristics to determine in-pit tailings storage feasibility. The project scope defined geotechnical and hydrogeologic site conditions through field investigations and in-situ pump testing. Tierra Group developed a 3D groundwater model to evaluate the potential interaction between tailings supernatant and groundwater. Following the Feasibility Study, Tierra Group completed an alternatives analysis comparing in-pit tailings storage with the Stage 7 Esperanza TSF expansion.

Crimea Diversion Channel Construction Quality Assurance (CQA)

Tierra Group provided CQA and field engineering services during the diversion channel construction.

Crimea Tailings Storace Facility (TSF) Phase 2 Feasibility Design

Tierra Group conducted a dam breach and inundation assessment and a feasibility-level design for the Tajo Crimea In-Pit Tailings Disposal Facility Phase 2 expansion. The Phase 2 design incorporated an embankment to provide additional (above minimum pit rim elevation) tailings storage capacity.

Crimea TSF Phase 2 CQA

Tierra Group provided CQA services (earthworks, geomembrane, and geotechnical monitoring instrumentation) for the in-pit TSF Phase 2 expansion and prepared the final as-built CQA report.