Martinson, R, Cooke, R & Stipo, N 2005, 'Cabildo Mine Backfill System', in R Jewell & S Barrera (eds), Paste 2005: Proceedings of the International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth, pp. 317-330, https://doi.org/10.36487/ACG_repo/563_21 (https://papers.acg.uwa.edu.au/p/563_21_Martinson/) Abstract: Minera Las Cenizas is planning to fill mined out sections of the Cabildo Mine (located 150 km north of Santiago) with tailings, to delay the construction of a new surface tailings storage facility for the mine. About 2.0 million cubic metres of void space is available to backfill tailings at a rate of 2,500 ton/d. The paper presents a study conducted to establish the feasibility of placing tailings into the mine voids. A trade-off study indicated that the optimum concen- tration to place the tailings is in the range of 62% to 64% by mass (i.e. as a high density thickened tailings). The paper describes the following aspects of the system: • Test work conducted for the project (rheology and sedimentation tests). • Conceptual trade-off study for optimum concentration deposition. • Thickened tailings pump and pipeline distribution system. • Method for filling the mine voids with tailings and recovery supernatant water. • Project initial costs. It is expected that the system will be commissioned in March 2006. 318 Paste 2005, Santiago, Chile Cabildo Mine Backfill System Martinson, R. et al.