Laserfiche WebLink
Colowyo Coal Company <br />2018 Annual Reclamation and Hydrology Report <br />GENERAL TRENDS - Groundwater <br />Colowyo currently samples each groundwater site for a variety of quality parameters. Of <br />all the parameters that are analyzed for, several key indicator parameters are identified. <br />These are lab pH, lab conductivity, TDS, sulfate, calcium, iron, magnesium, sodium and <br />elevation. Statistical analysis is completed and illustrates historical trends for each <br />parameter in Exhibit 1B. <br />Ground Water Data - The trend lines of the graphs in Exhibit IA were evaluated. No <br />significant trends were identified, and as such, the information is not included in <br />summary format. This analysis supports the assumed probable hydrologic consequences <br />of minimal impacts to surface water due to mining activity. <br />Summary of the indicator parameters for each ground water site is provided in the <br />following tables. <br />A-6 Well: <br />Parameter <br />Mean <br />Std dev <br />Range <br />Max. <br />Min. <br />Max at <br />Min at <br />Lab pH <br />7.77 <br />0.39 <br />1.9 <br />8.6 <br />6.7 <br />11/30/93 <br />11/21/02 <br />Lab Cond. <br />1110.04 <br />74.54 <br />512 <br />1440 <br />928 <br />05/01/85 <br />04/27/98 <br />TDS <br />695.29 <br />80.90 <br />750 <br />930 <br />180 <br />07/17/01 <br />03/13/93 <br />Sulfate <br />138.86 <br />50.08 <br />334.2 <br />430 <br />95.8 <br />07/17/01 <br />05/15/00 <br />Calcium <br />61.95 <br />16.26 <br />121.1 <br />169 <br />47.9 <br />11/18/97 <br />11/13/00 <br />Iron <br />0.25 <br />0.38 <br />1.81 <br />1.82 <br />0.01 <br />09/26/98 <br />11/18/97 <br />Magnesium <br />53.58 <br />15.33 <br />128 <br />169 <br />41 <br />11/18/97 <br />03/21/11 <br />Sodium <br />123.60 <br />18.04 <br />128.1 <br />146 <br />17.9 <br />3/11/08 <br />04/27/98 <br />Elevation <br />6897.89 <br />2.79 <br />14.53 <br />6902.53 <br />6888 <br />05/01/85 <br />07/31/00 <br />Evaluation of 2018 data for A-6 Well <br />No results from 2018 sampling were minimum or maximum values for any parameters <br />listed above during the monitoring period. Trend line analysis determined no significant <br />correlations over time. <br />Page 10 <br />