The traditional geotechnical assessment of tailings facilities has mainly concentrated on the stability of tailings dams, while relatively few studies have investigated the flow of tailings released after dam failure.
The oxidation of sulphide minerals within the vadose zone, and the accompanying dissolution of carbonate and aluminosilicate minerals within these tailings releases SO4, Fe(II) and other metals to the pore water.
Over 50 million cubic meters of mining tailings were released in the Rio Doce basin after the collapse of the Fundão dam (Samarco) in November 2015.
The upgrade of the code originated from the intent to investigate the complex rheological behaviour of tailings flows released following a dam failure, which till now has been the subject of relatively few studies, despite the serious consequences that the collapse of a tailings dam can induce.
Jeyapalan et al. (1983b) applied a Bingham plastic model (TFLOW computer program) to both the Aberfan case, in South Wales (1966), and to the Gypsum Tailing Dam incident, in East Texas (1966), and laminar flow behaviour of the released tailings was pointed out.
These results strongly suggest that the release of tailings to floodplains should be limited or prohibited, and that all tailings should be removed from floodplains following dam spills.
To assess the potential for metal release to tailings pore water by reductive dissolution reactions, a laboratory study was conducted on weathered tailings collected from the Nickel Rim mine tailings impoundment near Sudbury, Ontario, Canada.
When glucose was supplied as a C source, indigenous bacteria significantly enhanced the extent of As release from the tailings into solution under both aerobic and anaerobic conditions.
A previous investigation (Desogus et al. 2012c) identified a number of binder/additive mixtures that can reduce the heavy metal release by the tailings (Mulligan et al. 2001; Desogus et al. 2012c).
The reason is that sulfidic tailings from silver mining may release long-term toxic emissions to the aquatic compartment.
