Johnson, D, Moghaddam, R, Bin Ahmed, I & Laroche, C 2013, 'Comparative evaluation of surface disposal of thickened versus slurry tailings', in R Jewell, AB Fourie, J Caldwell & J Pimenta (eds), Paste 2013: Proceedings of the 16th International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth, pp. 289-302, https://doi.org/10.36487/ACG_rep/1363_22_Johnson (https://papers.acg.uwa.edu.au/p/1363_22_Johnson/) Abstract: The conceptual design of a Tailings Management Facility (TMF) for the proposed Hammond Reef gold mine in Canada investigated two options for surface disposal of tailings. Geochemical characterisation testing indicated that the tailings were not acid generating or metal leaching. Bench scale laboratory testing of the tailings’ rheological and dewatering properties were carried out to help define the properties of the thickened tailings at 68% solids content (by mass). Tailings dewatering test results indicated that the tailings could be efficiently dewatered to a solids content of 68% (by mass) using high compression thickeners. Furthermore, rheological test results indicated that the tailings could be pumped using conventional centrifugal pumps at this solids content. The results were used to support a comparison with slurry tailings deposition at 37% solids content (by mass). Conceptual TMF designs were developed for each option to comparatively evaluate the capital and operating costs of each option. The conceptual designs were based on the tailings’ geotechnical properties, available site investigation information, and water management requirements. The geometry of the proposed TMF site allowed for deposition of thickened tailings from a central discharge location to form a cone. However, it was determined that slurry deposition would be most efficient by end discharging from the north perimeter containment dam. A comparison was then made between the volume of perimeter containment dam construction required for the slurry and thickened tailings options. Comparative cost estimates of each option indicated that thickened tailings deposition was more cost effective compared to slurry tailings deposition. Thickened tailings deposition was chosen for the Hammond Reef project because it requires less dam construction, simplifies water management and has other environmental advantages, including reduced risk of tailings dam failure.