2018-04-23_REVISION - M2007031 (4)

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COLORADO •:;S , Department of Public �•' Health&Environment Water Quality Control Division Fact Sheet,Permit No. C00048939 The Scott Blue H gold placer mine is located in the NE 1/4 of S13, T25S, R7OW; on Galena Ave near Carbonate Street in Cripple Creek, CO 80813; at 38.75.4167 latitude North and 105.172222 longitude West in Teller County. The site occupies an area of approximately 1.4 acres. The entire Scott Blue II placer mine surface is disturbed from mining activities. The excavated area (mine pit) occupies the northern half of the mine, and intersects the Cripple Creek streambed along the northern facility boundary. Placer mining processing operations were previously conducted at the facility; however, as provided by the permittee, the sole industrial activity presently conducted at the facility is limited to the removal of existing raw materials from the facility for off-site processing. The permittee has indicated that processing will not occur onsite. Thus, this permit is written for discharges related to removing raw materials, but does not cover any discharges related to processing activities. Three ponds exist within the placer mine excavation (pit), and accumulate mine drainage from the excavated area. Two of the ponds have the potential to discharge to Cripple Creek, either passively or by pumping. The discharge point for both ponds is at the same latitude and longitude, therefore, one outfall (outfall 001) is identified for these discharges. Should the discharges from both ponds occur at the same time, this outfall location is representative of the resulting comingled discharges. In the absence of discharge flow rate information, the division established a design capacity at double the capacity of the pump used to return water to the receiving stream for water rights. The resulting design capacity of the facility is 0.1728 MGD (0.27 cfs). The technical analyses that follow include assessments of the assimilative capacity based on this design capacity. In the southern portion of the facility, stormwater runoff from the raw material stockpile flows toward the property boundary and not into the in-excavation ponds. This outfall is identified as outfall 002. Because ore processing is no longer conducted at the Scott Blue II placer mine site, the division determined that this facility is not subject to the provisions of the federal Effluent Limitation Guideline found at 40 CFR 440 Subpart M (Gold Placer Mining Subcategory). However, the division used best professional judgment to establish an effluent limit for settleable solids in this permit (see the Reasonable Potential discussion in Section VI of this fact sheet.) Should the permittee decide to begin ore processing at the facility, the permittee must notify the division as on-site processing may trigger the applicability of the federal ELG in its entirety. B. Chemical Usage The permittee did not specify any chemicals for use in waters that may be discharged. On this basis, no chemicals are approved under this permit. Prior to use of any applicable chemical, the permittee must submit a request for approval that includes the most current Material Safety Data Sheet (MSDS) for that chemical. Until approved, use of any chemical in waters that may be discharged could result in a discharge of pollutants not authorized under the permit. Also see Part II.A.1. of the permit. C. Wastewater Treatment Description Outfall 001-Mine drainage discharge from two settling ponds within the excavated area. Treatment is accomplished using gravity separation. Discharges can occur either passively or by pumping, and the discharge point for both is at a rip-rap structure into Cripple Creek. Outfall 002-Stormwater runoff discharge from the raw material stockpile at the southern portion of the mine that flows to the south-western portion of the property. VI. PERFORMANCE HISTORY A. Monitoring Data Page 3 of 17 4300 Cherry Creek Drive S., Denver,CO 80246-1530 P 303-692-2000 www.colorado.gov/cdphe/wgcd r;7 John W.Hickenlooper,Governor I Larry Wolk,MD,MSPH,Executive Director and Chief Medical Int/ • p:et peutreos