Impactos dos acidentes em barragens de rejeito de mineração: uma revisão histórica

Abstract

ABSTRACT - The aim of this study is to critically analyse the data of accidents with mining tailing dams, acquired from 148 scientific articles, 11 technical reports, and 4 databases available online (Supplementary Material). The aspects addressed here involve the main causes, ores, type and magnitude of the socioeconomic and environmental impacts. Reports on dam accidents date from 1626, with 1994 being the year with the largest number of accidents. At the end of 2015, the Mariana accident, in Brazil, stood out as the incident with the largest volume of tailings released ever registered. More than half of the reported accidents were related to human error (59%), while natural processes (32%) were reported as the second most important cause of accidents. From the 60’s, a substantial increase in the number of events happened, especially with Cu and Au or several combinations of ores. The largest amount of accidents occurred in the Americas (51.1%), where The United States and Chile were the countries with more occurrences. About 31% of the incidents reported deaths and a wide number of homeless people as a result of the accident. Among the countries with accidents, all of them have legislation regulating the mining activities. Mineral exploration is indispensable for the global economy, thus new technologies are constantly under development to improve the extraction efficiency and minimize associated environmental impacts. However, there is an imminent need for greater control of the operations of dams and better use of tailings generated. Recycling of tailing is an essential step to be incorporated in the life cycle of the mined ores. Preventive actions, despite corrective actions, are more effective and less costly for the environment and for society. Therefore, better practices, higher low enforcements together with preventive actions are necessary to reduce the number of accidents.