Influence of tailings deposition environment on deposit homogeneity and interpretation of cone penetration test data : A case study from the Cerro Corona Mine

Gold Fields La Cima S.A. (GFLC) owns the Cerro Corona gold and copper mine in the Cajamarca district of Peru. MWH has been providing design and construction support services to GFLC since 2006. The Tailing Storage Facility (TSF) includes a centerline constructed rockfill dam with a low permeability core zone and a proposed ultimate height of 160 meters. Upstream stability of the dam was a specific focus of the design and required characterization of the impounded tailings near the upstream face of the dam. The tailings deposition environment at the facility has varied with time, being largely subaqueous during initial facility filling, then fluctuating between subaerial and subaqueous due to variations in pond level, and more recently achieving a subaerial beach of increasing length. Three investigation programs, which included sampling, vane shear testing (VST), and cone penetration testing (CPT), have been performed to characterize the impounded tailings for design purposes. This paper presents a summary of these programs and their influence on the design. It also discusses the apparent influence on the deposition environment on the deposited tailing characteristics and the development of a variable, site-specific cone factor (Nkt) for use in estimating peak undrained shear strength(Su) from the CPT data.Applied Science, Faculty ofMining Engineering, Keevil Institute ofUnreviewedOthe