Barrera, S, Becerra, M, Chacón, P & Quelopana, H 2011, 'Challenges in the design of pilot tests', in R Jewell & AB Fourie (eds), Paste 2011: Proceedings of the 14th International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth, pp. 93-100, https://doi.org/10.36487/ACG_rep/1104_09_Barrera (https://papers.acg.uwa.edu.au/p/1104_09_Barrera/) Abstract: The behaviour of tailings slurries, particularly at high concentrations, presents a significant number of uncertainties. To address this issue, it is common practice to perform pilot tests to verify or anticipate the expected tailings behaviour at large scale. In the last year three pilot tests were conducted on different kinds of tailings and conditions. The scaling and implementation of these tests present challenges derived mainly from the nature of a material formed by two phases and its tendency for sedimentation, the viscous behaviour of the fluid, the presence and variation in time of chemical additives, representativeness of tested material, differences in consultants/owners conceptual approach, etc. The pilot tests need to be designed in such a way that allows us to obtain key information and extrapolate this information to our real case. To achieve this, it is at least necessary to address the following types of definitions: (i) parameters to be analysed; (ii) conceptual model; (iii) tests specifications; (iv) model scale; (v) type of material and concentration levels to be tested; (vi) type and amount of material; and (vii) available equipment; among others. This paper describes the process in the design and start-up of a pilot plant oriented at studying the behaviour of a slimes slurry, highlighting the difficulties encountered and the ways of addressing and overcoming them. This paper does not analyse the test results, analysis which will be part of another document.