Mobility assessment of potentially toxic elements contained in flotation and cyanidation tailings dam from gold mine located in Brazil

In Brazil, the recurring environmental impacts due to insufficient inspection and inadequate management of potentially toxic mining tailings have raised significant concerns. The study concentrates on examining the mobility of elements in flotation (ft) and cyanidation (ct) tailings from gold mining operations, following successive extractions. The influence of extractants on the release of elements from both ft and ct samples, including As, Cd, Cu, Cr, Pb, Se, and Zn, was examined and compared to the ABNT NBR 10004:2004 standard. The samples were obtained from a gold mining company in Brazil. Sequential extraction tests for ft and ct samples were conducted to simulate weathering effects, using solutions of 0.1 mol L-1 citric acid, 0.1 mol L-1 acetic acid, 0.1 mol L-1 oxalic acid, 0.1 mol L-1 ammonium acetate, and distilled water at pH 5.5. The results revealed that the established limits for Pb and Cd under the ABNT NBR 10004:2004 standard were exceeded in a 1:1 tailing-to-extractor ratio. In ct samples, both elements surpassed the standard limits for all extractors, except for Cd when using water. In ft samples, Pb exceeded the limits with all acids, while Cd exceeded the limits only in the presence of acetic acid and ammonium acetate.