Sector-Specific Benchmark Values and Effluent Limitations: Sector - G-2. Discharges may be subject to requirements for more than one sector or subsector.
Link to this table

Subsector Parameter Benchmark Values
G2 Active Metal Mining Facilitiess Solids, Total Suspended (TSS) 100 mg/L 3
pH 4 6.0-9.0 SU
Hardness, Calcium & Magnesium, Calculated (as CaCO3)1 no benchmark value
Antimony, Total (as Sb) 0.18 mg/L
Arsenic, Total (as As) 0.680 mg/L
Cadmium, Total (as Cd) 1 0.0078 mg/L 2
Copper, Total (as Cu) 1 0.028 mg/L 2
Iron, Total (as Fe) 1.0 mg/L
Lead, Total (as Pb) 1 0.164 mg/L 2
Nickel, Total (as Ni) 1 0.938 mg/L 2
Selenium, Total (as Se) 0.040 mg/L
Silver, Total (as Ag) 1 0.0041 mg/L 2
Zinc, Total (as Zn) 1 0.234 mg/L 2

1The benchmark values of some metals are dependent on water hardness. For these parameters, the Permittee shall determine the hardness of the receiving water to identify the applicable ‘hardness range’ for determining their benchmark value. See Table 4 of Appendix B for hardness dependent benchmark values in accordance with Minn. R. 7050.0222 and Minn. R. 7052.0100.
2Values given are for total hardness of 100 mg/L only.
3If the Permittee is required to comply with Appendix A, part F.1, the benchmark value for Solids, Total Suspended (TSS) is 65 mg/L, instead of 100 mg/L.
4For purposes of benchmark pH monitoring, the Permittee is required to report instantaneous results only, and not a calculation of pH averages. pH measurements are logarithmic, and the Agency will be performing a logarithmic average for this parameter using the instantaneous results submitted.

This page was last edited on 17 August 2013, at 14:08.