Wisconsin Administrative Code
Department of Natural Resources
NR 200-299 - Environmental Protection Wisconsin Pollutant Discharge Elimination System
Chapter NR 270 - Ore mining and dressing
Section NR 270.042 - Effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT)

(a) Except as provided in this subsection, there may not be discharge of process wastewater to navigable waters from mills beneficiating mercury ores by gravity separation methods or by froth flotation methods.

(b) In the event that the annual precipitation falling on the treatment facility and the drainage area contributing surface runoff to the treatment facility exceeds the annual evaporation, a volume of water equivalent to the difference between annual precipitation falling on the treatment facility and the drainage area contributing surface runoff to the treatment facility and annual evaporation may be discharged subject to the limitations set forth in par. (a).