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Mr. Paul Bruss, P.E. <br />August 30, 2018 <br />Page 2 of 6 <br />3 and 4 which are located on the East Parcel have been recalculated based on the aerial <br />images in Figure 2. The new acreage is 15.3 acres. <br />Total pre -1981 Exposure Post -1981 Exposure <br />Permit No. WDID Exposure <br />(acres) (acres) <br />(acres) <br />52017-F 1705986 15.3 <br />M <br />15.3 <br />Valco has retained the portion of the Rocky Ford East pit property east of County Road 22 <br />("East Property"), which includes Ponds 3 and 4 as shown on the attached Figure 2, and <br />intends to backfill the remaining ponds on the East Property. According to correspondence <br />with the Applicant, Valco has analyzed the property and confirmed that there is adequate fill <br />material on site to completely backfill the remaining ponds on the East Property. <br />Additionally, Valco has obtained a lease agreement with the Upper Arkansas Water <br />Conservancy District to replace depletions through July 31, 2022. <br />In accordance with the letter dated April 30, 2010 from the Colorado Division of Reclamation, <br />Mining, and Safety ("DRMS"), all sand and gravel mining operators must comply with the <br />requirements of the Colorado Reclamation Act and the Mineral Rules and Regulations for the <br />protection of water resources. The April 30, 2010 letter from DRMS requires that you provide <br />information to DRMS to demonstrate you can replace long term injurious stream depletions <br />that result from mining related exposure of groundwater. The DRMS letter identified four <br />approaches to satisfy this requirement. In accordance with approach no. 1, a bond has been <br />obtained for $193,678 through the DRMS to assure that depletions from groundwater <br />evaporation do not occur in the unforeseen event, or events, that would lead to the <br />abandonment of the Rocky Ford East Pit. <br />DEPLETIONS <br />The Rocky Ford East pit is in the process of reclamation. This SWSP renewal is to replace <br />depletions resulting from evaporation from the ponds and from the water contained in the <br />previously mined product. Evaporative depletions have been calculated using the maximum <br />surface area of the pit, which is 15.3 acres of post -1981 exposed groundwater surface area. <br />Depletions have been lagged back to the Arkansas River using a Glover analysis with the <br />following inputs: <br />Distance from river: 3,020 ft <br />Distance from alluvial boundary: 8,720 ft <br />Transmissivity: 71,000 gpd/ft <br />Specific yield: 0.2 <br />Lagged depletions due to current SWSP operations were calculated to be 22.15 acre-feet for <br />the period August 1, 2018 through July 31, 2019 and 43.47 acre-feet for the period August 1, <br />2019 through July 31, 2020. Lagged depletions due torp for SWSP operations were calculated <br />