Velardeña, a polymetallic mine in Durango, Mexico, produces zinc, lead, and copper, and operates two upstream-constructed tailings storage facilities. In 2020, cone penetration tests (CPTu) with pore pressure dissipation (PPD) and sonic boreholes were conducted to evaluate tailings and develop a geotechnical model for stability analysis to support additional upstream raise designs. In 2022, after two more upstream raises, a new CPTu investigation aimed to validate and update the geotechnical model. Parallel borings and geophysical surveys assessed compressional and shear wave velocities at similar locations.
The results showed improved geotechnical conditions and increased CPTu parameters, potentially due to partial saturation and suction. Low pore pressure ratio (Bq) with increased tip resistance (qc) and sleeve friction (fs) suggested lower moisture content. Shear wave velocity values allowed microstructure assessment, confirming the link between increased CPTu parameters and material aging. Phreatic conditions indicated a drier environment, observed through pore water pressure profiles from CPTu soundings and PPD tests, even during active deposition cycles.
By SRK Canada
