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Loam is approximately 10" in depth, and should be completely salvaged for topsoil replacement. <br />The Aquolls and Aquets are more variable, but can reach up to depths of 48". Because a large <br />reservoir will be created on site, enough topsoil should be available for a replacement depth of 10" to <br />12." Please commit to salvaging all of the Altvan Loam in stockpiles and replacing to a depth of 10" <br />to 12" at the entire Pazker-Dersham site. <br />28. The NRCS recommends a seed mixture that is slightly different than the seed mixture provided by the <br />applicant. The recommended NRCS seed mixture consists of Western wheatgrass, Switchgrass, Sand <br />bluestem, Alkali Sacaton, Blue grama and Sideoats grama. Please see attached NRCS comments for <br />rates. In addition, the NRCS points out that the grass mix provided by the applicant lists lbs (PLS) <br />/acre but is actually 100% PLS/acre. The 100% PLS/acre figure should be multiplied by the <br />corresponding percent mix for the grass to provide the PLS/acre for that grass. <br />Rule 6.4.6 Exhibit F- Reclamation Plan Map <br />29. The reclamation plan map does not show the proposed topography of the area with contour lines of <br />sufficient detail to portray the depth and slope of the reclaimed areas. Please revise the reclamation <br />plan map to include contour lines of the reclaimed area. <br />Rule 6.4.7 Exhibit G- Water Information <br />30. The Division received comments from the Office of the State Engineer (OSE) regarding the proposed <br />application. According to the OSE, before a well permit can be approved the applicant must conduct <br />a field location of the site and document the locations of all wells within 600 feet of the permit area. <br />The applicant must then obtain a waiver of objection from all well owners with wells within 600 feet <br />of the permit area or request a hearing before the State Engineer. See the attached OSE letter for <br />Further detail. Please commit to not exposing groundwater until a well permit is obtained from the <br />OSE. In addition, once the well permit is obtained a copy must be submitted to the Division. <br />31. In accordance with Rule 3.1.6(1)(a), please explain how disturbance to the hydrologic balance will be <br />minimized during the mining and reclamation phase of the Parker/Dersham site. Please explain how <br />Hall-Irwin will be in compliance with Colorado Water Laws and regulations governing injury to <br />existing water rights. Tn accordance with Rule 6.4.7(2)(b), the Division requests that the applicant <br />identify and characterize the aquifer to be mined in or through. The Division also requests that the <br />applicant define or predict the cone of depression expected for any areas to be dewatered and dry <br />mined during the life of the operation. The cone of depression assessment should define, at a <br />minimum, the horizontal and vertical extent of drawdown expected. If during the assessment, the <br />applicant determines that a drawdown will occur offsite that may impact a current groundwater user, <br />the applicant should explain any mitigation measures to be implemented and trigger points that would <br />put mitigation measures into effect. <br />32. Hall-Irwin provided the names and address of well owners within 600 feet of the permit area. The <br />well permit numbers do not correlate with the well map located in the application. Please provide the <br />name and location of all wells in the surrounding area that maybe impacted by the proposed mining <br />operation (please note that this maybe further than 600 feet as indicated in the application). <br />33. It appears that the Pazker/Dersham site is within the 100-yeaz floodplain of the South Platte River. <br />Please provide the flood elevarions(s) to be expected under a "worst case" flooding scenario and <br />specific mitigation measures that will be implemented to minimize the potential for any offsite <br />impacts. Legible copies of the Flood Insurance Rate Maps ("FIRM") through the mine reach would <br />facilitate the Division's review. <br />34. Please explain how water from dewatering of the Parker/Dersham site will be managed to protect <br />against pollution of surface of groundwater both during and after the mining operation (Rule <br />6.4.7(2)(c)). <br />