2021-10-28_HYDROLOGY - M2008017 - Laserfiche WebLink

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Broken Arrow Investments, LLC 801 8th Street, Suite 130 Greeley, CO 80631 October 28, 2021 Mr. Eric Scott Environmental Protection Specialist State of Colorado Division of Reclamation, Mining, & Safety 1313 Sherman Street – Room 215 Denver, CO 80203 RE: Broken Arrow Investments, LLC – File No. M-2008-017 Derr Pit – Summary for October Water Level Reporting Dear Mr. Scott, Broken Arrow Investments, LLC is providing this summary letter to discuss and provide information in regard to the October off-site an on-site monitor wells and provide the dewatering volumes pumped for September. During the month of September a total of 2.45 acre-feet was pumped and discharged into the on- site recharge ponds within the Derr Pit. AgPro was able to get the normal monthly readings/measurements on all of the off-site wells for the October readings. No trigger levels were reached for any of the off-site wells that were measured. As discussed in our technical revision letter there are some on-site wells that were removed due to the slurry wall construction and those wells are no longer in place. Monitor Well 11 is now accessible and is in the interior (inside the slurry wall) of the pit. Most of on-site monitor wells saw an increase in the elevation of the water levels. The water level elevations in the monitor wells on the Phase 1-4 portion of the pit went down on the south side by 0.29 and 1.05 feet and up on the north side by 1.09 feet. The decrease on the south side was due to not pumping as much to the recharge ponds since the slurry wall has been completed. The north side increase was due to the slurry wall has been completed. The water level elevations in the monitor wells on the upper terrace of the permit area increased by 0.49 feet for MW-14, increased by 0.23 feet for MW-15, increased by 0.92 feet for MW-16, increased by 2.05 feet for MW-17 and increased by 0.23 feet for MW-18.