2005-01-04_REVISION - M1999120 (2)

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potential for impacts to groundwater exists. Please indicate how [he hydrologic balance of groundwater in and around the permit site will be minimized and monitored. 8. Rule 6.4.7(1) requires the operator to directly state if surface water or groundwater will be affected by [he mining operation. The applicant has located wells within 600 feet of the affected land. It is not clear in the application materials, however, what aquifer these wells are tapped into, and the potential for impacts to these wells as a result of mining activities. Any wells tapped into the shallow, alluvial aquifer near the site will most certainly be impacted by [he mining operation. In accordance with Rule 6.4.7(2)(6), the Division requests that the applicant identify and characterize the aquifer to be mined in or through. The Division also requests that the applicant define or predict the cone of depression or shadow and mounding effect expected for any areas to be dewatered and dry mined or as a result of installation of a slurry wall. The cone of depression and assessment of other effects should define, at a minimum, the horizontal and vertical extent of expected impacts. If during the assessment, the applicant determines that a drawdown or shadow effect will occur offsite that may impact a current groundwater user, the applicant should explain any mitigation measures to be implemented and trigger points that would put mitigation meazures into effect, 9. Please describe how the drawdown of the pit or shadow effect will impact the structural integrity of the surrounding wells; surface water drainages; activities which rely on groundwater in the vicinity of the site; vegetation on or near the site, including the cottonwood trees in the riparian area near the South Platte River; and the wetlands located on the site. 10. The application states, "There will not be any significant effects on surface water from the proposed amendment area. Little Dry Creek and the East Lateral of [he Lupton Bottoms Ditch will not be mined, and mining will be set back at least 25 feet from these features." The Division has concerns that there may be effects on the amount of water conveyed in these structures if these structures leak and the groundwater level around the structures is lowered az a result of mining activities. Please indicate whether this issue has been investigated and the results of that investigation. If this issue has not been address, please investigate the potential impacts [o the water conveyed in these ditches and submit the results to the Division for review, 11. The site is located in the 100-year flood plain of the South Platte River. Please submit a flood control plan for the site. Rule 6.4.8 Exhibit H- Wildlife Information 12. In a letter received by the Division, November 28, 2004, Scott Hoover, of the Division of Wildlife (DOW), has submitted concerns related to impacts on the South Platte River riparian corridor in the Golden Pit area. The DOW has recommended a setback of 200 to 300 fee[ from the tree line of the river bottom. The letter conveys additional concerns related to the prairie dog colony on the expansion site. A copy of this letter was forwarded to the Applicant. Please indicate how the concems conveyed by the Division of Wildlife will be addressed in [he mining plan. Rule 6 4 12 Exhibit L -Reclamation Costs I3. In that the Applicant is proposing to address the manner in which each phase of the expansion area will be mined and reclaimed just prior to the commencement of mining in that area, and that the plans will be addressed in the form of a Technical Revision (TR) for each phase, the Division will calculate the bond amount for each phase when [he TR for that phase is submitted to the Division for review. Rule 6.4.19 Exhibit S -Permanent Man-made Structures 14. Division staff is reviewing the Geotechnical Stability Exhibit separately. Any adequacy review comments related to this exhibit will be addressed in a separate letter at a later time, Because an objection was filed, this matter must be set for a hearing before the Mined Land Reclamation Board. The tentative date for the hearing is January 19 or 20, 2005. However, the Division will need to make a recommendation by January 10, 2005. Please be advised that the L.G. Everist Fort Lupton Sand and Gravel Mine 112(c} Amendment (AM-OI) Application may be deemed inadequate, and the application may be denied on January 10, 2005 unless the above mentioned adequacy review items are addressed [o the satisfaction of [he Division in a timely manner allowing for adequate time to review the responses. If you feel more time is needed [o complete your reply, the Division can grant an extension to the recommendation date. This will be done upon receipt of a written waiver of your right [o a recommendation by January 10, 2005, and request for additional time. This must be received no later than the deadline date.