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Bowie has provided additional discussion regarding the potential intrusion of groundwater at Gob Pile # 3 <br />starting on proposed Volume XI, page 6. Bowie states, "[t]he intent of each subdrain is to capture water <br />from the fire mountain canal and direct it away from the gob pile. There has been no groundwater, seeps, <br />or springs identified in the footprint, so there is no need to have the east underdrain match the design and <br />configuration of the west subdrain." When reviewing the original engineering report by HBET, "Stability <br />Evaluation Gob Pile 93" (Volume XI Coal Mine Waste Disposal Area No. 3), groundwater conditions <br />were evaluated based on a set of piezometers BG06-01 through BG06-07 (G3-1 through G3-7 on Map 09 <br />- Hydrological Monitoring Location Map) that are located within the footprint of Gob Pile 93. The <br />piezometers showed groundwater levels to be well below surface level or were dry with the exception of <br />BG06-02. BG06-02 is located upgradient of Gob Pile 93 just adjacent to the Fire Mountain Canal and <br />showed groundwater levels at a depth of approximately 19 feet bgs. Based on this information it can be <br />assumed groundwater intrusion into Gob Pile 93 is unlikely and water levels in BG06-02 were from the <br />seepage known to exist from the Fire Mountain Canal. With the additional discussion starting on <br />proposed Volume XI, page 6 added, Bowie has addressed my concerns regarding the potential of <br />groundwater intrusion into Gob Pile #3 and I have no additional comments regarding this item. <br />Additionally, as discussed, there is a naming discrepancy between what is found in Bowie's PAP for the <br />piezometer designations in Volume XI Coal Mine Waste Disposal Area No. 3 and on Map 09 - <br />Hydrological Monitoring Location Map. Volume XI Coal Mine Waste Disposal Area No. 3 designates <br />the piezometers as `BG06" while Map 09 designates them as "G3". If necessary, Bowie may need to <br />update the PAP ensure the piezometer naming designations are the same. <br />This concludes my review of Bowie's TR-122 and if you have any questions, feel free to contact me. <br />Sincerely, <br />Zach Trujillo <br />Environmental Protection Specialist <br />(303) 866-3567 ext. 8164 <br />Zach.Trujillogstate.co.us <br />Bowie No. 2 Mine TR-122 Memo January 27, 2021 <br />