Chaponnel, J & Wisdom, T 2018, 'FLSmidth Colossal filter – demonstration plant', in RJ Jewell & AB Fourie (eds), Paste 2018: Proceedings of the 21st International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth, pp. 53-62, https://doi.org/10.36487/ACG_rep/1805_04_Chaponnel (https://papers.acg.uwa.edu.au/p/1805_04_Chaponnel/) Abstract: FLSmidth has installed and is operating a tailings dewatering demonstration plant at a concentrator in the Atacama region in Chile. The intention of the plant is to demonstrate the full-scale capabilities of our newest large-pressure filter for tailings, dubbed the Colossal filter press. It is intended to demonstrate the capabilities of one large filter press, where a number of the smaller filters would be required to process the full plant tailings. The dewatering plant is installed along the tailings line after the tailings thickeners in the vicinity of the tailings pond. The plant is designed to dewater 10,000 tpd of filtered tailings. The filtered tailings contain roughly 82 wt% solids, compared with approximately 52 wt% solids in the thickened tailings feed stream. Clarified filtrate is pumped to a clean water pond for reuse in the concentrator. Components of the plant include a feed slurry tank, filter feed pumps, one Colossal filter with drip trays, an innovative hybrid apron belt feeder, bridge crane, takeaway conveyor, radial stacker, filtrate equalisation tank, clarifier, floc system, pumps, and instrumentation. With the Colossal filter installed, commissioned and in operation, FLSmidth provides a paper containing the results that have been gathered thus far, with the intention of presenting all of the results that have been gathered prior to the 21st International Seminar on Paste and Thickened Tailings. The design philosophies, commissioning challenges and operational data associated with building and operating a large format filter are reviewed. Keywords: tailings, dewatering, filtration