Abstract

Mining is the most important economic activity in Chile, which is the largest copper exporter in the world. However, mining has significant environmental impacts, such as generating large amounts of solid waste. Due to the high moisture content of solid waste, physical stabilization problems can arise at disposal sites as a result of aqueous solutions trapped in solids not draining by gravity. Electroosmotic drainage has been proposed as a technique to reduce moisture and thus increase the stability of disposal sites. However, the question arises whether the volume of drained solution depends on the percentage of fine matter in the solid matrix. The experimental work reported here, based on an experimental factorial design, was carried out to address this question. The first part consists of an experimental design with synthetic solid matrices. The percentage of fine particles and the initial moisture level were defined as factors with three levels. The volume of drained liquid was defined as the response variable. The results showed that electroosmotic drainage was more efficient than gravitational drainage when the moisture content and the percentage of fine material were at their highest levels. The effect of the factors and their interaction was corroborated by an ANOVA. An equation was developed to describe the relationship between the response variables and the factors. Finally, considering the application of the technique in mining, tests were conducted on tailing samples and solid leaching residues. The tests showed that the technique is effective with tailings due to the high content of fine material and the initial moisture level. However, it was not effective with leaching residues due to the low initial moisture level and the low fine particle content. (C) 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.orgilicenses/by-nc-nd/4.0/).