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• The Wash Plant is currently operating year round, which results in a considerable amount of stockpiling <br />during the winter months, since the materials cannot be properly processed and compacted due to the <br />below freezing [emperamres and the lazge amount of snowfall. <br />Seemented Construction: In the original report, CTL/Thompson suggested that the pile be constructed in <br />segme s which extend from north [o south across the RDA, as shown in Detail 7 on Figure 5. This <br />method would be approoriate if the waste coal materials were free draining, as originally assumed. <br />However, based on dle chazacteris[ics of the processed waste coal and the production rate of the process <br />plant, a considerable amount of space is required to stockpile and drain the waste coal materials before <br />they can be placed in a compacted lift. To accommoda[e these materials, the contractor has had to }~ i,~,M,,,,`~ <br />stockpile the waste coal materials across the en[ire RDA and they have begun to place an compac[ ese <br />materials in the southern half of the RDA after they have dried out. Based on our experience widt dre <br />construction of the pile as of this date and the characteristics of the waste coal materials being placed in <br />the pile, we recommend that the requirement for the pile to be constructed in segments,. working from _ <br />north to south, be waived. We do not believe that waiving this requirement will be detrimental to the <br />stability of the pile. <br />• Vertical Construction: The original design report prepared by CTL/Thompson, also showed a suggested <br />detail for vertical construction of the RDA and the cover materials, as shown in Detail 9 on Figure 5. <br />The detail indicates that dre waste coal materials should be placed and compacted along the westem <br />portion of the pile (A) first and then the eastern 100' of waste coal (B) should be placed and compacted. <br />We strongly disagree with this type of construction sequencing and believe that the stability of the pile <br />may be reduced if this procedure is followed. We believe that the risk of a failure zone developing <br />between the two zones is greater in this type of constmc[ion sequencing. We recommend that the <br />/compacted lift (A) be extended out to the edge of the pile and that the cover materials be placed after the <br />outer face has been properly compacted. This would provide a more uniform embankment fill and <br />eliminate the possible failure surface which could occur along the transition between azea (A) and area <br />(B). We discussed this detail with Mr. Ronald McOmber of CTL/Thompson, the principal who <br />reviewed the original report prepared by CTL/Thoropson, and be concurs that this detail was probably <br />put in the report by mistake and that it was originally developed fora "zoned" embankment. In the <br />original report prepared by CTL, they refer to a much lazger waste coal refuse disposal azea, which was <br />[o be constructed to eas[ of the exis[ing RDA and was designed to hold 20 million cubic yards of waste <br />coal. This larger pile was to be constructed as a "zoned" embankmen[, with the interior of the pile, area <br />(A), being a non compacted zone and area (B) being a compacted zone. <br />• Temoorarv Road Construction: It is our unders[anding that there is some concern as to the location of <br />the temporary haul road which is presently being used to haul the waste coal materials [o the westem <br />Job No. 97-3216 Nartbwest Colorado Consultanu, Inc. Page 8 <br />