Table 6 Hydrochemical index of sandstone fracture water from the 13 coal system.
Index | Na+ | Ca2+ | Mg2+ | Cl– | SO42– | HCO3– |
---|---|---|---|---|---|---|
Minimum value | 1.54 | 46.62 | 31.10 | 8.40 | 10.86 | 72.14 |
Maximum value | 15.11 | 67.10 | 39.52 | 10.03 | 15.71 | 79.58 |
Average | 10.09 | 52.04 | 37.29 | 9.02 | 13.56 | 76.77 |
Standard deviation | 3.36 | 4.71 | 1.96 | 0.49 | 1.19 | 1.61 |
Coefficient of variation | 0.33 | 0.09 | 0.05 | 0.05 | 0.08 | 0.02 |