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Ms. Jennifer S. Lindahl Page 2 of 9 <br />December 3, 2018 <br />Mining at Stage 1 was completed in July 2016. The exposed ground water surface area within <br />Stage 1 is 6 acres in the northern portion of this cell and 7 acres in the southern portion of this <br />cell. The total ground water surface area at Stage 1 remains at 13 acres. <br />Mining at Stage 2 was completed by the end of 2016. Currently exposes a ground water surface <br />area of 7 acres and is filled to a depth of 15 feet. RMCC plans to allow Stage 2 to fill to a total <br />surface area of 14 acres and a depth of 20 feet in January 2019. <br /> <br />Mining at Stage 6A was completed mid-2017. Stage 6A currently exposes a ground water surface <br />area of 1 acre and is expected to remain at 1 acre. Water from Stage 6A will be used to <br />construct the slurry wall at Stage 6C/6D. <br /> <br />Mining at Stage 6B was completed in March of 2018. Stage 6B currently exposes a ground water <br />surface area of 3.8 acres and is expected to increase slightly to a ground water surface area of 4 <br />acres in 2019. <br /> <br />Mining at Stage 3 began in June 2017 and was completed in early 2018. Stage 3 currently exposes <br />a ground water surface area of approximately 1.0 acre and is expected to remain at 1 acre until <br />it is completely backfilled in the spring of 2019. This Stage 3 will be backfilled with overburden <br />from other stages which will fully eliminate the evaporation depletions. <br /> <br />RMCC estimates that mining at Stage 4 will continue through the end of 2019. A slurry wall was <br />constructed around the Stage 4 and a 90-day leak test was approved on May 23, 2018. Mining at <br />the Stage 4 will continue through the end of 2019. Stage 4 currently exposes 1 acre of ground <br />water. <br /> <br />Mining is expected to begin in 2019 at Stage 6C/6D following the installation of the slurry wall. <br />It is expected that Stage 6C/6D will expose 1 acre of ground water surface area by February <br />2019 and that the surface area will increase to a maximum of 6 acres of ground water by the end <br />of 2019. The 6 acres of exposed ground water surface area is expected to remain through the <br />end of the mining plan. <br /> <br />In accordance with the letter dated April 30, 2010 (copy attached) from the Colorado Division of <br />Reclamation, Mining, and Safety (“DRMS”), all sand and gravel mining operators must comply <br />with the requirements of the Colorado Reclamation Act and the Mineral Rules and Regulations <br />for the protection of water resources. The April 30, 2010 letter from DRMS requires that you <br />provide information to DRMS to demonstrate you can replace long term injurious stream <br />depletions that result from mining related exposure of ground water. The DRMS letter identified <br />four approaches to satisfy this requirement. <br /> <br />In accordance with approach nos. 1 and 3, you have indicated that a bond has been obtained for <br />the new Morton-Holton Lakes site that can cover the cost of lining, to prevent the exposure of <br />ground water. The current bond amount for the new Morton-Holton Lakes site is $4,150,000.00. <br /> <br />Depletions <br />The projected depletions for Stages 1, 2, 6A, 6B, 3, 4, and 6C/6D are resulting from evaporation, <br />water washed for the mined product, dust control, water for slurry wall construction, and the <br />additional fill of Stage 2. The Applicant proposed to replace evaporation from exposed ground <br />water at the Morton-Holton site based upon evaporation atlases in NOAA Technical Report NWS