Examination of the Effects of Solids Content on Thickened Gold Mine Tailings Sedimentation and Self-Weight Consolidation

• Published in: Geotechnical testing journal 2019-11, Vol.42 (6), p.1493-1517
• Main Authors: Bonin, Michaël Demers, Cabral, Alexandre R., Nuth, Mathieu
• Format: Article
• Language: English
• ISSN: 0149-6115; 1945-7545
• DOI: 10.1520/GTJ20180094

Thickening is being increasingly adopted by the mining industry because of its economic and environmental attributes, such as decreased amounts of water released following deposition and a smaller footprint of the tailings site. This study presents an assessment of the continuous process of sedimentation and the self-weight consolidation of slurry and thickened mine tailings. The results of a series of settling column tests performed with specimens with solids contents between 50 % and 72 % are presented and discussed. Lower solids contents that are more characteristic of slurry tailings were also included to cover a wide range of settling behavior. High-precision monitoring of pore water pressure was used to identify the transition from sedimentation to self-weight consolidation, which likely occurs between solids contents of 65 % and 68 % for this material, and it highlighted the fact that the combination of these two settlement processes accelerates ue dissipation. The displacement results for the tailings–water interface corroborate values in the technical literature related to the settlement of suspensions. Equilibrium was reached within a narrow time range (i.e., 400 to 500 min) despite the wide range of initial solids content in the slurries tested (i.e., 50 % S to 65 % S).