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Groundwater Quality Monitoring Plan <br /> 3.1 Baseline Data Collection <br /> To initially evaluate the baseline data, a normal distribution and a 95 percent confidence <br /> interval around the mean will be used to establish a baseline range of values. This is a <br /> standard statistical analysis commonly used for data management to establish an <br /> anticipated range of naturally occurring values that may occur. Water quality changes <br /> within the baseline data could be related to (a) seasonal variations, (b) changes in <br /> precipitation recharge, (c) spatial variations within an aquifer due to heterogeneous <br /> geologic conditions and/or (d) changes in water levels and hydraulic gradients with time <br /> that could affect water flow in the aquifer. Therefore, there may be a need to update the <br /> baseline data over time because the data has changed due to a particular change in <br /> natural conditions at the mining site. <br /> It is impractical to conduct extensive statistical analysis on every water quality <br /> parameter tested. Several "indicator parameters", i.e., water quality parameters that <br /> would be used to identify potential water quality degradation, will be selected for <br /> statistical analyses and charting. Volatile organic or semi-volatile organic hydrocarbons <br /> (VOC and SVOC) will be utilized as present or absent in any initial phases of monitoring <br /> and as needed to show increases or decreases in concentrations. To accomplish <br /> monitoring of VOCs and SVOCs they will be analyzed for baseline sampling and then <br /> only once a year at the most, unless detected and confirmed. After the initial five <br /> quarters of baseline data is collected, sampling will occur annually for specific <br /> parameters that are determined by the baseline data. Prior to starting the mining, <br /> sampling will be conducted within 90 days. <br /> 3.2 Indicator Parameters <br /> Indicator parameters are considered the most likely to change based upon conditions <br /> developed during the mining activities. However, the changes in indicator parameters <br /> do not confirm that pollution is occurring at the site, and only that conditions are <br /> changing in the water quality parameters. A further in-depth review of the groundwater <br /> quality would be needed to determine whether mining is resulting in any type of pollution <br /> in the aquifer. <br /> Site specific information at a mining site with similar locations and circumstances along <br /> the South Platte River approximately 12 miles upstream near Brighton, CO, can be <br /> useful in early evaluation and indicator selection at the LGE-WF site. Statistics <br /> information from some of the parameters in the South Platte River site approximately 12 <br /> miles upgradient are as follows: <br /> FgAjMOLEN LG Everist Monitoring Plan <br /> s ASSOCIATES Page 5 of 7 <br />