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Work plan DRAFT 6 <br />rOA Due to the discontinuous nature of the strata of the Williams Fork, the lateral extent and <br />spatial continuity of these units is not clear at this time. Part of the planned work <br />includes developing a better understanding of the correlation and continuity of these <br />units. These four units have been identified as possible monitoring targets as discussed <br />in Section 2.4. The alluvium /colluvium of the various creeks represents the fifth <br />groundwater monitoring target. Groundwater monitoring will be conducted to determine <br />potentiometric levels and water quality in each of the potential water - bearing units. <br />Hydraulic information collected during drilling along with single -hole hydraulic tests in <br />monitoring wells will be used to characterize hydraulic parameters. <br />Well construction diagrams which show typical monitoring well completion designs for <br />each targeted strata are presented as Figures 3.1 through 3.5. Wells will be <br />constructed to meet relevant monitoring well construction requirements. It is anticipated <br />that direct rotary drilling techniques will be used to install all monitoring wells. Drilling <br />fluids will likely be limited to air, water and foam. <br />Groundwater monitoring wells have been tentatively located on Plan 1 to provide <br />information both up- gradient and down - gradient of the operation while remaining outside <br />the proposed pit footprint. Table 3.1 summarizes the purpose of each monitoring <br />location, the strata being targeted, preliminary construction information and the sampling <br />and analysis schedule. These targets are preliminary and may be adjusted as <br />appropriate as additional drilling information becomes available. <br />There are four bedrock monitoring locations identified on Plan 1. Each location will be <br />evaluated for the installation of monitoring wells in all four of the bedrock monitoring <br />targets. It is not clear at this time how far to the southwest these units will be saturated <br />so some flexibility will be required in the final selection of the upgradient bedrock <br />monitoring locations. <br />Alluvial wells will be located upstream and downstream of the proposed operation on <br />each of the major drainages, including: Straight Gulch, Collom Gulch, and Jubb Creek. <br />In addition, a well will be located on Little Collom Gulch downstream from the valley fill <br />and above its confluence with Collom Gulch. An alluvial monitoring well already exists <br />on the lower portion of Jubb Creek so six new alluvial wells will be installed during this <br />field season. <br />Single -well aquifer tests will be conducted on each monitoring well to estimate formation <br />permeabilities. These tests will be performed after the well has been properly developed. <br />Estimates of permeability will be used to determine potential inflow rates to the mine. <br />Water quality samples will be collected from both bedrock and alluvial monitoring wells <br />on a quarterly schedule. Field parameters will be measured on a monthly schedule. <br />Table 3.2 lists the analytes and field parameters which will be reported for all <br />groundwater monitoring sites. <br />Dedicated sampling equipment such as submersible pumps, bailers or sampling tubes <br />may be used to collect each sample. Stagnant water will be purged from each well prior <br />to collecting each sample. Field parameters, including pH, Electrical Conductivity (EC), <br />and temperature will be monitored during purging to document that all stagnant water <br />has been removed and representative groundwater is being sampled. Samples will be <br />filtered in the field with a 0.45- micron filter. <br />2572 -R1 Colowyo Coal Company, L.P. <br />Water Management Consultants <br />