R 425.406 Protection of water.

Rule 406. (1) A permittee shall conduct groundwater and surface water monitoring according to the approved monitoring plan as described in R 425.203(g) during mining operations and during the postclosure monitoring period. (2) An operator shall design, construct, and abandon a monitoring well as prescribed in R 323.2223(4). (3) Water monitoring shall include the collection of water quality samples from groundwater and surface water, groundwater levels, and surface water levels and discharge rates. The design of the water monitoring systems shall be based on all of the following: (a) The environmental impact assessment. (b) The local geology and hydrology. (c) Groundwater and surface water conditions specific to each activity. (4) Surface water monitoring sites shall be designed and located to adequately assess the impact of a specific mining activity on surface water. (5) Groundwater monitoring sites shall be designed and located as follows: (a) Leachate monitoring wells shall be located within, or as close as physically practicable to, a storage or disposal facility for the following materials that are determined to be reactive, to determine the geochemical conditions of the facility.: (i) Overburden. (ii) Ore. (iii) Waste rock. (iv) Tailings. (b) Compliance monitoring wells shall be located as close as physically practicable but not more than 150 feet from the mining activity being monitored. However, the department may approve an alternative water monitoring location if the operator demonstrates the location is protective of the environment and public health and safety, and a closer location is not feasible or effective. (6) A permittee shall notify the department and shall institute an increased monitoring program as may be directed by the department at such time as sampling of leachate monitoring wells or compliance monitoring wells detects concentrations of a solute 2 standard deviations above the long-term average background level for 2 consecutive sampling events. (7) An action level is reached at such time as sampling of leachate monitoring wells and compliance monitoring wells detects either of the following: (a) Concentrations of a solute that equal or exceed ½ the level between the long-term average background and the drinking water standard for two consecutive sampling events. (b) Concentrations of hydrogen ion, expressed as pH, that differ from the long-term average background by 0.5 units or more for 2 consecutive sampling events. (8) When an action level is reached as described in subrule (7) of this rule, then the permittee shall proceed in a timely manner to do the following: (a) Implement increased monitoring as approved by the department. (b) Conduct a source investigation to determine the cause of the change in water quality and provide a report on the investigation to the department. (c) Implement a plan for response activity as approved by the department if the change in water quality is determined by the department to be caused by a release associated with a mining activity that is the responsibility of the permittee. (9) Failure of a permittee to meet the requirements of subrules (6) to (8) of this rule shall constitute a violation of this part. Implementing actions required by this rule does not relieve the permittee from other obligations under this act.