2012-03-12_REPORT - C1982056 (2)

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Tables 50 through 52 provide summaries of the 2011 Water Year data collected at each 303 series (303 -1 through 303 -3) spoils spring. Table 50a and 51a provide a period of record statistical summary of collected data at sites 303 -1, and 303 -2, respectively. Figure 109 provides a graphical representation of period of record field conductivity for spoil spring 303 -1. Water quality parameters for series 303 -1 were typically within previously established ranges. 3.5 Natural Spring Monitoring Two natural springs, SW 1 and SW2, located over previously mined areas in the Southwest Mining District required semiannual monitoring during 2011. Prior to mining, SW -1 typically flowed throughout the year, while SW2 flows were sporadic. In recent years flows at SW -1 have been minor, and in the case of SW -2, non- existent. However, flow was observed in SW -1 in May, but not in September 2011. Analytical values were within historic limits. No flow was observed in SW -2, in May and September of 2011. In May 2011, a spring and seep survey was also conducted in the northern mining district to identify potential discharges to Fish Creek. No new or significant springs were identified in 2011. The northern mining district is located within the Twentymile Park Syncline. The predominant lithologic unit nearest the surface and occupying most of the basin is the Lewis Shale, which can be upwards of 700 feet thick. The lack of significant bedding planes, faulting, or fracture zones in this area may account for the lack of springs in the central portion of this basin. The few seeps observed in the basin may be the result from surface weathering of the Lewis Shale, which may allow some accumulation of water beneath overburden. This may result in a short period of seepage immediately following spring runoff. 3.6 CDPS Discharge Sites Under State of Colorado Department of Public Health and Environment (CDPHE), Colorado Discharge Permit System (CDPS) permit No.'s CO- 0027154, CO- 0036684, and CO- 0042161, eleven discharge points are monitored throughout the year. Note that CDPS has also been referred to as the National Pollutant Discharge Elimination System (NPDES) in previous AHRs. Monitoring results (CDPHE Colorado Discharge Monitoring Reports, or DMRs) are copied to DRMS in accordance with CDPS requirements. Tables 54 through 60 provide 2011 and historical data summaries for those CDPS outfall points. Figures 112 through 115 provide graphical representations of the 2011 flow rate and field conductivity data for Pond D at the Foidel Creek Mine and for Pond E at the Fish Creek Tipple. Figure 116 depicts period of record total recoverable iron data for Pond E. Note that ponds A (former Outfall 001 A), and H (former Outfall 009A) were deactivated following Phase III Bond release of the Eckman Park area, and were subsequently removed from the newly amended CDPS permit on January 1, 2002. Construction Dewatering Permit COG - 850051 In July 2006, Twentymile Coal contacted CDPHE regarding the addition of this site (drainage for 6MN Pad area and construction dewatering pond) and later submitted a Temporary Construction Dewatering — Wastewater 13