## 4 Discussion

Table 2: Estimation of the quantities of elements extracted as solid crystals (tons per year) and the annual economic revenues (kUSD) obtained after deparation of the three samples along a year for a minimum treatment of 10 m\({}^{3}\) ASEC system (the system could be scaled to thousands of m\({}^{3}\) per day if necessary). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Annual Production (kg)**} & \multicolumn{3}{c}{**Annual Potential Revenues (kUSD)**} \\ \hline  & **Rio Tinto** & **Tharsis** & **Dredged Mat.** & & **Rio Tinto** & **Tharsis** & **Dredged Mat.** \\ \hline Be & 0.009 & 0.007 & 0.007 & Be & 0.009 & 0.008 & 0.007 \\ \hline Bi & 0.000 & 0.034 & 0.637 & Bi & 0.000 & 0.001 & 0.013 \\ \hline Ca & 41.87 & 204 & 417 & CaCO\({}_{3}\) & 13.06 & 63.54 & 130 \\ \hline Cd & 3.09 & 3.26 & 0.15 & Cd & 0.008 & 0.008 & 0.000 \\ \hline Ce & 1.87 & 2.60 & 7.77 & Ce & 0.007 & 0.010 & 0.029 \\ \hline Co & 31.39 & 23.83 & 2.46 & Co & 1.543 & 1.171 & 0.121 \\ \hline Cr & 1.01 & 1.44 & 5.95 & Cr & 0.008 & 0.011 & 0.048 \\ \hline Cu & 274 & 647 & 106 & Cu & 2.323 & 5.481 & 0.901 \\ \hline Dy & 0.382 & 0.479 & 0.541 & Dy & 0.169 & 0.212 & 0.240 \\ \hline Er & 0.203 & 0.244 & 0.271 & Er & 0.005 & 0.006 & 0.006 \\ \hline Eu & 0.080 & 0.102 & 0.171 & Eu & 0.023 & 0.029 & 0.049 \\ \hline Fe & 8444 & 7062 & 6656 & Fe & 887 & 742 & 699 \\ \hline Ga & 0.21 & 0.24 & 1.19 & Ga & 0.160 & 0.181 & 0.898 \\ \hline Gd & 0.44 & 0.57 & 0.78 & Gd & 0.011 & 0.015 & 0.020 \\ \hline Ho & 0.07 & 0.09 & 0.10 & Ho & 0.004 & 0.005 & 0.006 \\ \hline In & 0.10 & 0.07 & 0.05 & In & 0.054 & 0.039 & 0.029 \\ \hline K & - & 121 & 545 & KCl & - & 60.48 & 272.30 \\ \hline La & 0.719 & 1.022 & 4.633 & La & 0.003 & 0.004 & 0.017 \\ \hline Li & 4.11 & 6.70 & 5.92 & Li & 0.054 & 0.088 & 0.078 \\ \hline Mg & 4035 & 3469 & 1128 & MgCl\({}_{2}\) & 3228 & 2775 & 902 \\ \hline Mn & 385 & 353.8 & 50.83 & Mn & 12.0 & 11.06 & 1.59 \\ \hline Na & 123 & 1121 & 1434 & NaCl & 7.64 & 69.52 & 88.93 \\ \hline Nd & 1.19 & 1.71 & 4.12 & Nd & 0.150 & 0.215 & 0.520 \\ \hline Ni & 12.87 & 4.78 & 2.58 & Ni & 0.209 & 0.078 & 0.042 \\ \hline Pb & - & 10.81 & 44.40 & Pb & - & 0.023 & 0.096 \\ \hline Pd & 74.6 & 73.6 & 174 & Pd & 0.100 & 0.098 & 0.232 \\ \hline Pr & 0.250 & 0.363 & 0.998 & Pr & 0.026 & 0.038 & 0.104 \\ \hline Se & 0.937 & 1.521 & 2.024 & Se & 0.024 & 0.039 & 0.052 \\ \hline Sr & - & 6.156 & 28.049 & Sr & - & 0.083 & 0.379 \\ \hline Sn & 161 & 1489 & 17,957 & Sn & 4.05 & 37.51 & 452.28 \\ \hline Sm & 0.331 & 0.473 & 0.830 & Sm & 0.004 & 0.006 & 0.011 \\ \hline Tb & 0.067 & 0.084 & 0.100 & Tb & 0.110 & 0.138 & 0.164 \\ \hline Th & 0.072 & 0.242 & 0.851 & Th & 0.005 & 0.018 & 0.062 \\ \hline Tl & 0.006 & 0.162 & 0.104 & Tl & 0.047 & 1.307 & 0.840 \\ \hline Tm & 0.018 & 0.023 & 0.020 & Tm & 0.925 & 1.167 & 1.020 \\ \hline Yb & 0.167 & 0.195 & 0.219 & Yb & 0.002 & 0.003 & 0.003 \\ \hline Zn & 953 & 550 & 132 & Zn & 2.317 & 1.339 & 0.322 \\ \hline Total (kg) & 16,987 & 18,170 & 31,853 & Total(kUSD) & 4171 & 3787 & 2588 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._Therefore, after a year of depuration of mining residues with ASEC treatment (10 m\({}^{3}\)/day), the Rio Tinto River samples depuration would provide 4 million USD in potential revenue and 3.7 million USD in potential revenue from Tharsis samples depuration. In the case of dredged material depuration with the ASEC system, the potential revenue would reach 2.5 million USD for the selected elements. After discounting expenses that decrease the extraction ratio and considering other impurities, the revenue calculations for the selected elements would be between 0.76 and 1.2 million USD (a significant increment might positively affect these numbers). The study of [PERSON] et al. (2018) also supports the cost-effective secondary mining of residues from Rio Tinto and Tharsis mine residues to obtain a potential gross profit above one hundred USD based on the recovery of Ag, Zn, Pb, Sb, Cs, Bi and As.