2011-03-14_REPORT - C1982056 (3)

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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, SW1 and SW2, located over previously mined areas in the Southwest Mining District required semiannual monitoring during 2010. 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 2010. Analytical values were within historic limits. No flow was observed in SW-2, in May and September of 2010. In May 2010, 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 2010. 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. 0 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 2010 and historical data summaries for those CDPS outfall points. Figures 112 through 115 provide graphical representations of the 2010 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 001A), 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 Discharge Application, which was subsequently approved (Outfall 001A under CO-G072272). CDPHE requested preliminary analyses of this water for alkalinity, COD, pH and TDS. A sample was collected and analyzed for these parameters. A discharge channel was constructed in late July 2006, and weekly monitoring of discharge from outfall 001A began in August 2006. Note that water was pumped from the sedimentation pond through 13