2014-07-11_REPORT - C1980007 - Laserfiche WebLink

Home Browse Search

West Elk Mine 2013 Annual Hydrology Report 48 hydrographs are presented in Appendix B and the field and laboratory surface water quality data are summarized in Appendix C. Tables and graphs of the Sylvester Gulch and NFGR temperature monitoring data are presented in Appendix I and Appendix J, respectively. 5.1.1 Impacts to Area Stream Water Quality As mentioned previously, surface water quality data are collected for permit- specified parameters at monitoring stations throughout the permit area, in order to detect potential impacts of mining activities to surface water resources (Appendix C). Potential impacts to water quality in area streams are determined by comparing recent water quality and flow data to baseline values while considering effects of climatological factors, such as drought or high precipitation in areas near mining activity. Monitoring sites with values greater than 10 percent over comparable baseline maximums are noted in the discussion below. Field pH values were used for comparison when they were available, as the holding time for the lab pH is typically exceeded due to the shipping time required for samples to reach the analytical lab. In general, water quality parameters that are above 10 percent over baseline maximums are likely due to natural variations in climate or flow conditions on the day the sample was collected. Impacts that appear to be directly linked to mining activities are noted. It should also be noted that baseline values are based on limited data and only give a general indication of seasonal variability. In WY 2013 none of the tested parameters were elevated 10 percent or more above maximum baseline values at the following surface water monitoring locations: Lower North Fork of the Gunnison River, Lower Minnesota Creek, Lower Dry Fork, Lick Creek, Deep Creek Ditch, Upper Raven Gulch, Lower Raven Gulch, and Minnesota Reservoir Flume. The Upper Sylvester Gulch, Lower Gribble Gulch, Horse Gulch, East Gulch, east of Horse Gulch, Box Canyon, and Deer Creek sites were dry and there are no water quality data for these sites in WY 2013. There are no baseline data for comparison for Upper Minnesota Creek (WWE, 2001). Data from two sampling rounds (extended parameter suite; May 2013 and August 2013) plus one duplicate for each sampling round were collected at the Upper North Fork monitoring site in WY 2013. The August 2013 dissolved sodium concentration at this site was 7.0 mg /L (6.8 mg /L duplicate) compared to the baseline maximum of 5.7 mg /L. Data from one sampling round (extended parameter suite; May 2013) were collected at Middle Sylvester Gulch in WY 2013. In WY 2013, four parameters in Middle Sylvester Gulch were elevated 10 percent or higher than the maximum baseline values. The chloride concentration was 35 mg /L compared to the baseline maximum of 10 mg /L; electrical conductivity (EC) was 1,010 µmhos /cm compared to the baseline maximum of 800 µmhos /cm; the sodium adsorption ratio (SAR) value was 5.29 compared to the baseline maximum SAR of 3.02; the sulfate concentration was 106 mg /L compared to the baseline maximum of 80 mg /L. The elevated concentrations of these parameters are not believed to be mine related, as there was no MWPF discharge (MCC, 2014). Data from one sampling round (May 2013) plus one duplicate were collected at Lower Sylvester Gulch in WY 2013. Four parameters in Lower Sylvester Gulch in WY 2013 were at least 10 percent above the maximum baseline values for the sample: Electrical June 2014 HydroGeo, Inc.