All these dewatering processes are designed to recirculate the maximum amount of water to the plant and offer alternatives for the tailings solids disposal to the older solution of pumping to tailings pond, or dam.
Based on the pore water profiles and the geochemistry of the tailings solids, a relative mobility scale of Fe=Mn=Ni=Co>Cd Zn>Cr=Pb>Cu can be determined.
Geochemical analyses yielded a strong inverse correlation between the Fe/As molar ratio in the tailings solids and the corresponding concentration of dissolved As, which is attributed to the adsorption of As to secondary 2-line ferrihydrite present in the tailings.
Gangue and tailings are both solid wastes produced by mining processing.
Cemented paste backfill (CPB) is an engineered mixture containing up to 60% solid tailings, and 3 7% binder (often) and water.
With the exception of LC1-M1, algalgal mat sample with 1.0 wt% S, all tailings and biogenic solid samples contained less than 0.5 wt% S. The remaining elements in the ordination (Cd, Sb, Ni, Hg, and Cu) are considered chalcophilic elements, but only Cd is strongly positively correlated with S by the PCA (Figure 2, bottom).
Another PCA was performed on the chemical data of ore, mill tailings, and biogenic solids listed in Table 2.
Linear combination, least-squares fits constrained in part by PCA results were then used to quantify arsenic speciation in XAFS spectra of tailings and biogenic solids.
Comparison of the leachable fraction of metals and ions in tailings at a solid-to-water ratio of 1 10 (Table 3) with the leaching limit values for inert waste [35] (Table 6) shows that the requirements are fulfilled only for the Gura Rosiei and Sesei impoundments, while the other tailings cannot be considered of no contamination risk.
Among the solid wastes, tailings are one of the highest worrisome, particularly when they have low pH and high concentrations of heavy metals (Shu et al. 2001).
