Laserfiche WebLink
Peabody Sage Creek Mine <br />SL -3 Phase III Bond Release Request <br />July 2014 <br />Mine NPDES Pond 008 basin) confluence. It is approximately four miles downstream of the <br />PSCM permit boundary. PSCM discharges into Fish Creek by way of NPDES Pond 004 <br />(NPDES4), which is located in the headwater of Cow Camp Creek. Table 1 provides the Fish <br />Creek alluvial GWPOC water quality standards established in TR -47. Table 2 provides a statistical <br />summary of the water quality for the years 2011 to 2013 collected at Well SFAL72. The only <br />standard that was exceeded was iron (0.35 mg /1, dissolved) with values ranging between 2.88 and <br />5.16 mg /1. However, total recoverable iron values for the last three years upstream at all spoils <br />springs (SSSPG9 at Seneca; and SSSPGI and SSSPG2 at the PSCM) were less than 0.71 mg /1; <br />and NPDES discharges (NPDES008 at Seneca and NPDES4 at the PSCM) were less than 0.32 <br />mg /1. Therefore, the high iron values observed at Well SFAL72 are not likely to be the result of <br />discharges from the Seneca II Mine or PSCM. The high levels of iron displayed at Well SFAL72 <br />are more likely the result of naturally occurring organic matter and plant debris present in the <br />alluvium (Hem, 1989, pg. 77) at this particular location. <br />The GWPOC well in the Grassy Creek alluvium is Well SGAL70 (aka, Well GW- S70 -A). This <br />well is located about 0.6 miles downstream of the PSCM permit boundary. PSCM NPDES <br />Outfall 002 (NPDES2) discharges into Grassy Creek by way of Little Grassy Creek. Table 3 <br />provides the Grassy Creek alluvial GWPOC water quality standards established in TR -47. Table 4 <br />provides a statistical summary of the water quality for years 2011 to 2013 collected at Well <br />SGAL70. No exceedances of those standards were observed on samples collected from Well <br />SGAL70 in the past three years. <br />TR -47 also addressed bedrock aquifers. Bedrock GWPOC wells were deemed not necessary <br />based on the absence of the potential for the mine to negatively impact the quality of bedrock <br />ground water. This is due to the low hydraulic conductivities of the bedrock units. Other factors, <br />including attenuation and dilution further limit water quality impacts to a close down gradient <br />proximity. Furthermore, confining layers isolate mine- impacted water bearing units from the <br />nearest usable aquifer, the Trout Creek Sandstone, which lies approximately 300 to 400 feet <br />below the Wadge Coal seam and approximately 60 to 100 feet below the Wolf Creek Coal seam. <br />25 <br />