Abstract

ADUVIRE, Osvaldo. Costos de cierre en depósitos de desmontes y presas de relaves generadores de acidez . REV. MAMYM [online]. 2022, vol.7, n.2, pp.3-9. ISSN 2519-5352.

Abstract Mineral extraction and the beneficiation process genérate mining waste such as waste rock and tailings that are generally stored in surface deposits. This occupation of land and the requirement for proper environmental management mean that technical, economic, legal, environmental and social requirements are considered in the design of these deposits. During the operating life of the mining waste deposits, controls are implemented to reduce the impact on the environment and surrounding communities through continuous monitoring programs included in the mandatory environmental certifications, such as environmental impact studies, but once the mining operation is completed, the closure stage begins, when the site of these deposits, which store mining waste such as mine waste and tailings, is rehabilitated. In order to choose the closure alternative for these deposits, a series of factors are taken into account, such as the location of the site, the physical and chemical properties of the mining waste, the construction method of the deposit and mainly the geochemical behavior of the waste in the long term, for which it is important to estímate the probability of alteration of the mining waste in contact with water and oxygen, as well as the capacity to genérate acidity and leaching of metáis, among others. The closure scheme of the deposits must ensure physical, chemical, hydrological and biological stability post-closure. One of the biggest problems in achieving stability of mining waste such as waste rock and tailings with the potential to genérate acidity is contact with oxygen and water; therefore, to achieve chemical stability, the use of impermeable or semi-permeable barriers and coverings is used. Each alternative includes a series of closure activities, which induce certain execution costs, generating different direct and indirect costs in the closure budget. This paper presents the variations of closure costs for different mine waste deposits, identifying the variables with greater sensitivity and influence on mine closure budgets, in order to optimize their management from conception to rehabilitation, using the best available techniques in their design, construction, operation and closure.

Keywords : Closure costs; Landfill rehabilitation; Tailings dam rehabilitation.

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