Sagittarius Mines Inc. (SMI)/Xstrata Copper (XCu) retained Klohn Crippen Berger Ltd. (KCB) to undertake a geotechnical design for the Tailings Storage Facility (TSF) dam as part of the Feasibility Study (FS) for the proposed Tampakan Copper-Gold mine in Mindanao, southern Philippines. The dam site is located in the Bong Mal River valley and has 2200 mm annual precipitation with a representative earthquake magnitude of M7.8. The dam foundations generally comprise of meta-sedimentary rock origin at the right abutment and pyroclastic rock original at the left abutment.
The completed TSF dam is proposed to be 280 m high and will be built using a central low permeability soil core, downstream processed granular filter and drain, and soil/rockfill shells. The dam zoning has been selected to maximise the use of local natural materials, and will be raised annually to accommodate tailings and water storage requirements.
Key activities undertaken for the geotechnical design of the TSF cofferdam, starter dam and ultimate dam include:
- Stability analysis under static, post-earthquake conditions during dam operation and after closure;
- Seepage analysis to estimate the amount of seepage and determine the location of the phreatic surface within the dams;
- Static deformation estimate of the dam using the 2D plane strain finite difference computer program FLAC (Fast Lagrangian Analysis of Continua);
- Dynamic deformation estimate using semi-empirical approach methods;
- Embankment dam zoning; and
- Filter design and construction material specification.
Scope of Services:
- Geotechnical Assessment
- Engineering Geological Assessment
- Tailings Storage Facility Dam Design
- Embankment Dam Zoning
- Slope Stability Analysis
- Filter Design
- Seepage Analysis
- Dam Foundation Design
- Construction Material Assessment
- Static and Dynamic Deformation Analyses
- Construction Schedules and Specifications