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Ms. Sandrn L. Brown <br />•© Colorado Division of Minerals fr Geo[og~ <br />Decenrher 13, 1998 <br />Pagc 3 <br />for material disposal within the designated area and taking into consideration the possibility <br />that all or portions of the shop/warehouse facilities might be designated and retained as <br />permanent structures in the future. At this time, Kerr is proposing to retain the <br />shop/warehouse building and associated outside lighting as permanent structures in <br />conjunction with the proposed postmining land use (refer to TR-19, Kerr Mid-Term Review <br />Responses and accompanying permit revisions). Kerr wishes to retain the approved <br />shop/warehouse disposal area designs[ion in the even that retention as a permanent <br />structure is not approved or is not feasible. The smaller disposal area on the southeast side <br />of the shop/warehouse pad, as shown on Map 37A and designated for disposal of coal fines <br />and steel demolition debris from the tipple, is approximately 0.7 acres in size and the <br />shop/warehouse pad in this area is approximately 15 feet high. The volume capacity of this <br />area is approximately 5,650 cubic yards ((0.7 acres x 43,560 fr'/acre x 15 k /3) / 27). <br />5) Rule 4.11.4 requires that placement and storage shall ensure that leachate and surface runoff <br />do not degrade s:trface or gro:snd water. Please address this requirement for Goth the tipple <br />and mine site locations. <br />Response: Demolition debris disposal in the tipple area will be limited to sub-grade <br />placement of concrete demolition debris. As an inert material, the potential Eor generation <br />of any associated harmful leachate from the buried concrete is negligible. In addition, burial <br />will occur in the sub-grade portion of the crusher building, which is above the normal water <br />table, has a concrete floor and walls, and will be covered by a minimum of 2 feet of suitable <br />cover (see response to Comment 7) and revegetated. All of these factors will limit the <br />potential Eor ground water degradation. The potential for surface water degradation will be <br />adequately addressed by both the specified cover and surface grading and revegetation. <br />As documented in Section 779.14(x) of the Kerr Permit Application document, analysis of <br />coal seam materials indicates that they are not potentially acid-, alkaline-, or toxic-forming. <br />Disposal of coal fines and steel demolition debris in the mine area will, therefore, no[ resul[ <br />in any potentially harmful leachate. Similar to the tipple area, the proposed disposal site is <br />above the normal water table and the materials will he covered by a minimum of 4 feet of <br />suitable cover and revegetated. The proposed disposal site is not in a natural drainage and <br />has been located and configured so that any runoff will be diverted around or off the sides of <br />the disposal area. These considerations effectively address the potential for surface or <br />ground water degradation. <br />6) The sub-grade portion of the crusher building is proposed as the disposal site for al/ concrete <br />debris. How was the 40 yd' of concrete demolition debris determined? R'/hat is the volume of <br />the sub-grade portion of the crusher building? How far be(orv ground level is it? <br />Response: Both the volume of concrete demolition debris and the capacity of the sub-grade <br />portion of the crusher building were addressed in the 7/97 memo to Jim Burnell referenced <br />in the response to Comment 1. The following summarizes the relevant information from <br />that memo: <br /> <br />