Geotechnical Investigation — SMHL Tailings Storage Facilities (4 Sites), VIMETCO Sierra Rutile

ISC was appointed by VIMETCO SMHL to carry out geotechnical investigations at four tailings storage facilities — TSF 1, TSF 2, TSF 3, and TSF 5 — at the Sierra Rutile mine site in Moyamba District. The investigation was designed to characterise embankment and foundation conditions at each facility and to support stability assessment and long-term performance monitoring.

Fieldwork comprised three investigation methods at each facility: test pitting at embankment toe lines with in-situ DCP and permeability testing; CPT-u testing at 15 locations across the four dams (3 per dam) for subsurface profiling, strength parameters, and pore pressure response; and drilling of 12 boreholes with SPT at 1.0 m intervals and Shelby tube undisturbed sampling.

All soil samples were transported to the ISC laboratory in Freetown for full characterisation including moisture content, particle size distribution, Atterberg limits, compaction, and shear box testing. A comprehensive geotechnical report with engineering analysis and design recommendations was delivered.