The second phase of the Yaoure site was handled as a technical lining program requiring the expansion of the tailings storage facility (TSF) under tropical climate conditions. Since intense rainfall regimes and high humidity necessitated narrowing the geomembrane welding windows, on-site panel deployment, positioning, and extrusion welding operations were concentrated in the early morning hours; the wrinkling effect caused by surface heating in the afternoon was minimized through panel overlap and temporary anchoring planning.

HDPE geomembrane panels were joined using the double-track fusion welding method; air pressure testing was applied to every weld, and vacuum box testing was applied at critical transitions to record containment integrity. In slope transition zones, anchor trenches were stepped according to the soil profile, and the sub-membrane drainage geometry was revised based on the long-term hydrostatic load that the stored fine-grained tailings would generate.

Since the Phase 2 scope was executed in a manner ensuring hydraulic continuity with the existing operational cell, the tie-in details between the old and new liner were rehearsed on-site one-to-one; the QC team reported non-destructive testing (NDT) results to the employer's representative at the end of each shift, leaving no delay in the commissioning schedule.