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(Pages 8 and 9 of Permit No. CO-0045675) S. Discharee Point 002: (Permit Limitations, Best Management Requirements, and Schedule of Compliance) Beginning no later than the effective date of the permit and lasting through September 30, 2005, the permittee is authorized to discharge from outfall number 002, the seepage front in the Rito Seco alluvial groundwater which results from the backfilled West Pit as shown io figure 2 of the permit. In accordance will[ the Water Quality Control Commission Regulations for Effluent Limitations, Section 62.4, and the Colorado Discharge Permit System Regulations, Sections 61.8(2), 61.8(3)(n) and 61.8(3)(r), 5 C.C.R. 1002-61, the permittee shall continue to implement the following limitation, compliance schedule and Best Management Practices (BMPs). The attainment of applicable water quality standards will be implemented and evaluated through the application of the following limitation, compliance schedule and Best Management Practices (BMPs) that are designed to monitor and control the water quality and quantity discharging from the West Pit to the Rito Seco alluvial aquifer. Specifically, the limitation, compliance schedule and BMPs are those activities that address groundwater flows associated with the two componenu of the seepage front. These two components include: (1) the seepage front flaw that resulted historically in the formation of surface seeps along the arroyo sidewall of the Rito Seco directly adjacent to the window, and (2) the seepage front flow within the Rito Seco alluvial aquifer that exists as a zone of affected groundwater that flows along the naturally occurring hydraulic gradient parallel to sub- parallel to the Rito Seco. The activities will include the following specific requirements. The elevation of the ground water table shall be measured on a weekly basis in the West Pit backfill extraction well BF-4 for the purposes of regulating the flow and quality of water in that portion of the seepage front that contributed historically to the formation of surface seeps. This data shall be summarized and repoRed for outfall 002 on the discharge monitoring reports (DMRs), and the data will be used to evaluate compliance with the following permit limitation: The average monthly groundwater level elevation measured in the backfill extraction well BF-4 must be equal to or lower than an elevation of 8583 feet above mean sea level (ft. amsl). Additionally, the historical seeps are paR of this component of the seepage front flow and, due to natural variation in the flow of groundwater in the vicinity of the historical seeps, the following compliance schedule will be followed in the event that there is flow at the seeps. 1. Monthly visual inspection shall be conducted, and the permittee shall repoR any seepage flow that is associated with the area of historic seepage expression, as is identified in figure 2 of the permit. 2. In the event flow at the seep(s) is observed, a groundwater level measurement will be taken from the West Pit backfill monitoring well BF-4 and alluvial aquifer monitoring wells M-16 and M-17. The permittee will be required to communicate to the WQCD the occurrence of the seep(s) within 24 hours and provide verbal updates to the WQCD every second day thereafter. 3. If the measured groundwater level elevation at BF-4 is at or below the compliance elevation (8583 ft amsl), then the permittee will continue to observe any flow at the seeps while conducting daily measurements of the groundwater level elevation measured at BF-4 throughout the period of time flow occurs at the seep(s). The regular monitoring program would then be followed after cessation of flow at the seep(s). 4. If the measured groundwater level elevation at BF-4 is above the compliance elevation (8583 ft amsl), the permittee will be required to submit within 30-days a response plan to the WQCD. The response plan must address the cause of the flow(s) and propose one or more response actions that would be developed in the context of the water quality, water quantity, the anticipated duration of flow from the seep(s), and the measured or projuted impacts the seep(s) would have on the water quality of the Rito Seco. In addition, the permittee will be required to initiate the operation of the seep collection system that was used historically to control the seep flow(s). Implementation of the response plan must be in accordance with a schedule approved by the WQCD. Additionally, the WQCD may reopen the CDPS permit to include any fuRher applicable requirements, based upon the results obtained from implementation of the response plan.