Evolution of Acid Mine Drainage Formation in Sulphidic Mine Tailings

Abstract

Sulphidic mine tailings are among the largest mining wastes on Earth and are prone to produce acid mine drainage (AMD). The formation of AMD is a sequence of complex biogeochemical and mineral dissolution processes. It can be classified in three main steps occurring from the operational phase of a tailings impoundment until the final appearance of AMD after operations ceased: (1) During the operational phase of a tailings impoundment the pH-Eh regime is normally alkaline to neutral and reducing (water-saturated). Associated environmental problems include the presence of high sulphate concentrations due to dissolution of gypsum-anhydrite, and/or effluents enriched in elements such as Mo and As, which desorbed from primary ferric hydroxides during the alkaline flotation process. (2) Once mining-related operations of the tailings impoundment has ceased, sulphide oxidation starts, resulting in the formation of an acidic oxidation zone and a ferrous iron-rich plume below the oxidation front, that re-oxidises once it surfaces, producing the first visible sign of AMD, i.e., the precipitation of ferrihydrite and concomitant acidification. (3) Consumption of the (reactive) neutralization potential of the gangue minerals and subsequent outflow of acidic, heavy metal-rich leachates from the tailings is the final step in the evolution of an AMD system. The formation of multi-colour efflorescent salts can be a visible sign of this stage.

Submarine Tailings Disposal (STD)—A Review

“…This chapter is taken from Dold [5] for the convenience of the reader and more details on this issue can be found in this reference and in another review in this Special Issue [1]. The problem of sulphide oxidation and the associated acid mine drainage (AMD), or more generally acid rock drainage (ARD), as well as the dissolution and precipitation processes of metals and minerals, has been a major focus of investigation over the last 50 years [34][35][36][37][38].…”

“…AMD occurs, when sulphidic mine waste is exposed to atmospheric oxygen and water, as occurs in waste rock dumps and mine tailings storage areas and in underground workings or on the walls of an open pit mine. Due to the problems of AMD formation and the geotechnical instability of mine tailings (fine milled material like sludge) impoundments (reviewed elsewhere in this Special Issue [1]), the mining industry is searching for alternative means of waste management, as this is one of the main issues confronting mining operations. Due to the aforementioned problems of on-land deposition of tailings, one option, which has recently regained atention is submarine tailings disposal (STD).…”

Improvement of Traditional Mining Tailings Storage Facilities

“…The mechanism of the generation of AMD is as follows [14] 3. When H + ions are generated, toxic metal ions in the tailings should be dissolved and AMD comes into being [15].…”

Environmental geochemistry of the abandoned Mamut Copper Mine (Sabah) Malaysia

“…Mines operating porphyry Cu-Au systems can potentially pose significant post-mining environmental impacts, because: (i) disseminated ore and large volume of these deposits require extensive open-cut operations with high tonnages of waste rock; (ii) with high throughput rates, large amounts of tailings are consequently produced; (iii) mining wastes contain reactive sulphide minerals particularly pyrite and (iv) these ore deposits typically contain igneous host rocks, and their alteration products, with low alkalinity producing capacity (McMillan and Panteleyev 1980;Plumlee et al 1999;Sinclair 2007;Dold 2014).…”