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David Berry -16- June 20, 1996 <br />67. The DMG's comments regarding blasting notification are noted. <br />68. BRL has hired Morrison Knudsen to prepare a geotechnical <br />investigation of the proposed disturbed area. The <br />geotechnical report will be utilized to assure that the <br />proposed coal handling facilities are not jeopardized by <br />geologic hazards. <br />69. Comments included above under section 2.05.3(2) pertain to the <br />potential exposure of the proposed coal mine waste and non- <br />coal processing waste facilities to impacts from the <br />geological hazards identified on the permit area. <br />WESTEC identified two geologic hazards at the site, as <br />specified by USGS geologic hazard maps of the area: rockfalls <br />and expansive soils. Rockfalls will create no risk to upset <br />any of the coal mine waste bank facilities; significant <br />rockfalls may require clearing if they interfere with <br />operations. Expansive soils in the area originate from the <br />Mancos Shale underlying much of the site. Expansive soils <br />become problematic when exposed to moisture. Moisture at the <br />site is controlled by an underdrain system and runoff control <br />ditches such that prolonged wetting of the shale is not <br />expected. Thus, the two identified geologic hazards of <br />rockfalls and expansive soils should not present a concern at <br />the coal mine waste pile. <br />70. The material balance section in volume 4 is not clear with <br />respect to topsoil salvage and availability for reclamation. <br />Of the four foot cover requirement, how much will be general <br />coverfill and how much will be topsoil. From reviewing the <br />baseline soils report, it would appear that at least two feet <br />of the final cover will consist of topsoil. Please expand the <br />discussion in this section to clearly explain the salvage and <br />redistribution related to both topsoil and other cover <br />material. <br />The material balance assumed 0.5 feet of topsoil placed on top <br />of 3.5 feet of cover fill. One excavation to determine <br />salvageable topsoil depths in the area of the waste bank was <br />conducted and indicated up to 27-inches may be available. <br />This one, randomly placed hole may not be representative of <br />conditions over the entire site. However, all available <br />topsoil in the area will be stockpiled during construction. <br />If topsoil volumes exceed the waste bank topsoil stockpile, <br />the remaining material will be placed in one of the other <br />three topsoil stockpiles on site. The Volume IV text will be <br />edited to reflect this. <br />Volume IV - ^Coal Mine Waste Bank Final Design for the Bowie <br />No. 2 Mine^ <br />