# Groundwater Mixing Process Identification in Deep Mines Based on Hydrogeochemical Property Analysis
## 4 Results and Discussion
It also observed that the hydrochemical types of all mixed groundwater samples transform to SO4\(\cdot\)HCO3-K + Na\(\cdot\)Mg, SO4-K + Na\(\cdot\)Ca, HCO3\(\cdot\)SO4-K + Na, SO4\(\cdot\)Cl\(\cdot\)HCO3-K + Na\(\cdot\)Mg, and HCO3\(\cdot\)SO4-K + Na\(\cdot\)Mg from SO4-K + Na. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{2}{c}{**Cation (mg/L)**} & \multicolumn{2}{c}{**Anion (mg/L)**} & \multirow{2}{*}{**Alkalinity**} & \multirow{2}{*}{**pH**} & \multirow{2}{*}{**TDS**} & \multirow{2}{*}{**Hardness**} \\  & **K\({}^{+}\) + Na\({}^{+}\)** & **Ca\({}^{2+}\)** & **Mg\({}^{2+}\)** & **HCO3\({}^{-}\)** & **SO4\({}^{2-}\)** & **Cl\({}^{-}\)** & **(mg/L)** & **(mg/L)** & **(\({}^{\circ}\)H)** \\ \hline C1 & 1030.31 & 80.18 & 48.06 & 346.34 & 1903.19 & 268.16 & 5.676 & 7.8 & 3693 & 22.30 \\ C2 & 284.99 & 108.96 & 75.67 & 384.11 & 585.56 & 197.46 & 6.269 & 7.8 & 1647 & 32.69 \\ C3 & 493.17 & 92.56 & 54.06 & 281.79 & 944.62 & 206.11 & 4.618 & 8.4 & 2178 & 25.42 \\ C4 & 872.30 & 80.36 & 41.28 & 302.29 & 1586.33 & 234.80 & 5.780 & 8.1 & 3129 & 15.42 \\ C5 & 1003.74 & 63.63 & 24.62 & 313.82 & 1759.74 & 250.86 & 5.140 & 8.1 & 3412 & 14.58 \\ C6 & 805.12 & 70.78 & 33.34 & 357.39 & 1368.65 & 215.51 & 6.321 & 8.0 & 2761 & 17.59 \\ C7 & 784.16 & 64.85 & 25.51 & 381.00 & 1300.39 & 213.06 & 6.244 & 7.8 & 2761 & 15.24 \\ C8 & 291.92 & 109.72 & 72.53 & 367.70 & 566.64 & 223.73 & 6.030 & 7.8 & 1646 & 32.08 \\ C9 & 551.33 & 105.73 & 52.66 & 362.09 & 1022.58 & 227.21 & 5.934 & 7.9 & 2317 & 26.94 \\ C10 & 430.88 & 137.05 & 78.97 & 295.33 & 1018.3 & 214.27 & 4.840 & 7.9 & 2242 & 37.39 \\ C11 & 330.19 & 144.53 & 83.50 & 268.24 & 877.53 & 207.07 & 4.396 & 8.1 & 1974 & 39.48 \\ C12 & 202.68 & 58.90 & 57.07 & 573.03 & 206.16 & 97.97 & 9.391 & 7.9 & 1206 & 21.40 \\ O1 & 193.3 & 10.63 & 27.01 & 314.81 & 83.19 & 82.37 & 353.81 & 9.4 & 1180 & 137.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Chemical properties of each groundwater sample. Figure 5: Piper diagram of all groundwater samples. The mixing ratios of all mixed groundwater samples are calculated according to the distances of each mixed groundwater sample to Sample O1 and Sample C1 in the diamond field in Figure 4 using Equations (1)-(3). The groundwater mixing ratios calculated from piper diagram were treated as initial values in the PHREEQC model to modify the value of simulation concentration of Cl\({}^{-}\). The mixing ratios calculated by the piper diagram and modified by the PHREEQC model were shown in Table 4.  
The difference between the mixing ratios calculated by these two methods can be explained in that the piper diagram only calculated the different groundwater mixing from concentrations, but did not consider the chemical reaction between different groundwaters; while PHREEQC model calculated the mixing ration based on the result of piper diagram, and moreover, considered the chemical reactions between different groundwaters and water-rock interactions. Therefore, mixing ratio values calculated by PHREEQC are more accurate. The results demonstrate that the mixing ratio of groundwater sample C12 is the highest, up to 0.905, which means the groundwater sample C12 mixed the most with groundwater in the Ordovician limestone karst-fissure aquifer system. The initial hydrochemical types of these groundwater samples changed after the evolution using the PHREEQC model. Hydrochemical type evolution at all the sampling points are plotted again in the