2010-07-27_PERMIT FILE - M2009076 (23)

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6.4.20(10)(b) The stormwater management design has been performed by a CO licensed professional engineer. See this design in Exhibit C and Exhibit E. A SWMP permit has been applied for with the CO WQCD. 6.4.20(11)(x) Clear Creek is located 2,800' to the south and 1,000' in elevation below the Tailings Impoundment affected area. Drainage from this area follows down Hukill Gulch. Historically, the drainage from this vicinity contains acid- runoff/drainage from the numerous abandoned mine waste rock piles and adits located throughout this normally dry gulch. Many of these sources are not within the control of Venture Resources (ie Colorado School of Mines owns over a dozen properties downgradient in this vicinity; one of which, the Edgar Union Lode, contains three large dumps that is 350' downgrade from the proposed Tailings Impoundment). A Colorado Discharge Permit is not required because there is zero process water discharge to surface waters and the process water is nearly 100% recycled back to the rill. However, DRMS has requested surface water quality data. and analysis. The area of study looks at the surface water of Clear Creek, within two miles downgradient of the proposed operation. This area is within Sections 34, 35, and 36 of Township 3 South, Range 73 West. The Colorado Water Quality Control Division (WQCD) has identified this portion of mainstream Clear Creek as COSPCL2c and it is referred to as the South Platte River Basin, Clear Creek Subbasin, Stream Segment 2c. This segment roughly follows the mainstream of Clear Creek from a point just below the confluence of Mill Creek to a point just above the Argo Tunnel Facility Discharge. Numeric standards are developed on a basin-specific basis and then adopted for particular stream segments by the WQCD. The standards for Stream Segment COSPCL2c, have been assigned to this stream segment in accordance • with Regulation No. 38 Classification and Numeric Standards South Platte River Basin, Laramie River Basin, Republican River Basin, Sniokey Hill Basin. Standards for some metals are shown in the regulations as Table Value Standards (TVS). Table Value Standards are derived from equations that depend on the hardness of the receiving stream. Other metals standards are based on, and adjusted accordingly to, historically elevated levels due to past mining activities and the naturally occurring geological deposits of sulfide minerals and heavy metals that are concentrated here. Refer to the appendix of this Exhibit T for the water quality standards: • CDPHE Water Quality Control Div., Clear Creek "Segment 2c" Standards Existing adjudicated water rights within this area have been studied through the CO Department of Water Resources; a list is attached in the appendix of this Exhibit T. In summary, these rights are listed as having a use of "industrial-other" and after further study it can be determined that these are for mining uses. Many water rights are transferred through Clear Creek to other points downstream. These uses comprise a broad range from municipal drinking water to irrigation water to industrial/commercial use. Additionally, Clear Creek is a popular recreational water body for rafting and fishing. Potential future uses could also be reasonably assumed to match the broad range of existing uses. 6.4.20(11)(b) Metal content in the water here is higher than other areas of the State and is highly variable. This can be attributed to variations in seasonal precipitation that result in highly irregular dilution/concentration conditions. USGS streamflow data is attached in the appendix of this Exhibit T showing the high variablility. • USGS Station 06716500 Clear Creek Strearnflow Data To illustrate the ambient water quality, data collected by the WQCD (Station 000132) and USEPA (Station CC-34) on Clear Creek was used. The sampling sites are the best data available representative of ambient water quality. The data period of record is from August 1999 to October 2005. A summary of this upstream data is attached in the • appendix of this Exhibit T: • US EPA Station CC-34 Clear Creek Surface Water Quality Data • CDP14E Station 000132 Clear Creek Surface Water Quality Data Page 26 of 31