Deschamps, T, Benzaazoua, M, Bussiere, B, Belem, T & Aubertin, M 2006, 'A Laboratory Study of the Hydro-Geochemical Behaviour of Paste Tailings Disposal', in R Jewell, S Lawson & P Newman (eds), Paste 2006: Proceedings of the Ninth International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth, pp. 255-265, https://doi.org/10.36487/ACG_repo/663_22 (https://papers.acg.uwa.edu.au/p/663_22_Deschamps/) Abstract: Cemented paste tailings are used regularly for underground backfilling of open stopes. This technique allows returning acid generating tailings underground, where the backfill serves as ground support. Paste tailings disposal (PTD) on surface have been proposed for some time as an alternative to “traditional” tailings impoundments (e.g., Cincilla et al., 1997), which may be difficult to rehabilitate and responsible for many geotechnical and environmental problems (W.I.S.E., 2005). This technique is already used at the Bulyanhulu gold mine (Tanzania), where tailings are densified, pumped, and deposited as a paste in thin layers (Theriault et al., 2003; Shuttleworth and Thomson, 2005; Theron et al., 2005; McMullen et al., 2005). In this particular case, no binder is added to the paste tailings. However, even if the technique is promising, the interactions of the paste tailings in the disposal area with the local environment are still not well understood. This paper presents complementary results ensuing from a study performed by Benzaazoua et al. (2004) which presented details on the experimental set-up and background information. More specifically, this paper focuses on: (i) the hydrogeological and geochemical behaviours of paste tailings disposal after a long curing time and (ii) the microstructural and chemical characterisation of the cemented paste tailings.