2011-02-25_REPORT - C1980005 - Laserfiche WebLink

Home Browse Search

higher than the CDOH standard of 100 ug/1. The cause of this elevated detection limits was a decision by the laboratory to dilute the sample prior to analyses in order to reduce the effects of interferences (primarily, high salinity). Ground Water Points of Compliance A GWPOC have been established for the Seneca II Mine. Attachment 7-3 (Tab 7) of the Seneca II PAP provides the details. The ground water standards for Fish Creek Alluvial Well SFAL72 are provided in this AHR on Table 7. The only Standard that was exceeded this year was iron with values of 4.64 and 3.66 mg/1. However, the maximum iron value observed this year upstream at Alluvial Well SBAL68 was 1.26 mg/l. Therefore, the high iron values observed at Well SFAL72 are not likely to be the result of discharges from the Seneca II Mine. The high levels of iron displayed at this well are likely the result of naturally occurring organic matter and plant debris present in the alluvium (Hem, 1989, pg. 77) at this particular location. Ground Water Quality Summary. The TDS trend at Well 68 was stable. No TDS trends can be discerned from Well 72 yet. No CDPHE agricultural ground water standards for were exceeded this year. With the exception of iron (see above), no GWPOC standards were exceeded this year. In the area surrounding Seneca II, ground water is not being pumped for irrigation or livestock watering purposes, nor has the CDPHE classified any aquifer in this region for any use. The above discussion is provided only to serve as a comparative basis to judge ground water quality. Domestic wells that provide drinking water for local residents are not from aquifers impacted by mining. Surface Wate Table 8 lists pertinent information on all NPDES, stream, and spring monitoring sites at the Seneca II Mine. A complete description of the old surface water monitoring program may be found on Pages 7-336 to 7- 6