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Binns, Janet <br />From: Kaldenbach, Tom <br />Sent: Wednesday, October 28, 2009 1:19 PM <br />To: Nettleton, Jerry <br />Cc: Binns, Janet; Hernandez, Daniel <br />Subject: Foidel Creek Mine (C-82-056), PR-8, Item 6, Impacts to springs <br />Attachments: schematic cross section.doc; FBR-2.pdf <br />Jerry, <br />The Division's responses to your email of October 27, 2009 are provided below <br />Perry Springs - Based on the submitted explanation indicating Perry Springs #1 through #5 have shown no <br />adverse impacts from previous nearby mining, the Division has no further comment regarding these springs <br />other than to request that the information on these springs be added to the previously requested table. <br />Underburden Springs - The submittal explains that the springs that are located in areas of underburden <br />exposures (Boeddeker Springs #1 and #2 and Coyote Spring) will not be affected by the proposed mining due to <br />their stratigraphic isolation from the Wadge Coal Seam and due to their shallow recharge sources. Please <br />evaluate the potential impact to these springs for the scenario in which ground water from the Trout Creek <br />Sandstone enters the workings in the western mining district from an unexpected fault as it has been suspected <br />of doing in the 2 West Main of the #5 Mine of the Eagle Mines in Moffat County (permit page 2.05-37, Eagle <br />Mines, Permit C-81-044). Although the Boeddeker and Coyote springs may have recharge from nearby shallow <br />infiltration, they also are hydraulically connected to the underlying bedrock unit which extends eastward into <br />the western mining district. Please also add the information on these springs to the previously requested table. <br />Gertie Spring and Livestock Spring #2 - Please add the information to the previously requested table for the <br />Gertie Spring and Livestock Spring #2, using values for hydraulic properties that are consistent with those <br />reported in Robson and Stewart, 1990, "Geohydrologic Evaluation of the Upper Part of the Mesaverde Group, <br />Northwestern Colorado, USGS Water-Resources Investigations Report 90-4020. A spring's location in <br />alluvium on the land surface does not necessarily prevent hydraulic connection to the underlying bedrock unit <br />(please see attached schematic cross-section). Regarding faults as permeability barriers, permeability can vary <br />greatly along a fault plane resulting in the fault plane being a barrier to flow in some places and a conduit for <br />flow in other places. Also, significant ground water flow across a fault is not necessary for a drop in the <br />regional potentiometric surface to extend across the fault. The drop in elevation of the potentiometric surface <br />caused by mine subsidence cracks would extend outward from the mine area due to the breach of the hydraulic <br />pressure system overlying the workings. This appears to have occurred in well FBR-2 (please see attached <br />hydrograph). <br />Spencer Spring #2, Bear Run Spring, House Spring #1 - Please provide the locations of these springs so that we <br />can determine if they need to be added to Map 15A. <br />Sincerely, <br />Tom Kaldenbach <br />Environmental Protection Specialist <br />Colorado Division of Reclamation, Mining and Safety <br />1313 Sherman St., Room 215 <br />Denver, CO 80203 <br />(303) 866-4923