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NMD (Panels 12 Rieht through 16 Riehtl(PR 99-051-The geology description provided in PR-03 can be applied to the <br />description for the NMD. One item to note is that TCC discontinued pumping from the Fish Creek Borehole for a <br />period of approximately 18 months. When pumping commenced the total recoverable iron and total dissolved solids <br />concentrations increased to approximately 17 mg/1 and 7200 mgJl respectively. TCC is applying caustic soda to reduce <br />the total recoverable iron concentration as is per its CDPI-)E discharge pemut. TCC believes the elevated <br />concentrations are the results of the water stagnating in the underground sump. Once this pool of water is discharged, <br />TCC believes the wncentration will return to levels previously reported for the Fish Creek Borehole. TCC will <br />continue to monitor the concentration, and anticipates the concentration to return to historic levels by late summer, <br />2000 or 2001. <br />In regards to futwe impacts, TCC will not discontinue pumping of the underground sump for the extended periods <br />of time. This will eliminate the potential for the above situation to occur in the futwe. Once mining is completed <br />at the facility, no further dischazging will occur. Based upon this, there should be no impact to the postmining land <br />use. <br />Coal Refuse Pile <br />The Coal Refuse Pile, located to the southwest of the Area 2 Pit, as shown on Map 24, Surface Facilities, has been <br />designed to hold approximately 3,000,000 cubic yazds of material. The refuse pile has been designed to <br />accommodate placement and permanent disposal of coal refuse materials generated from the preparation plant, <br />excess coal development waste material from the mine, or a combination of preparation plant and mine waste <br />material. This material or combination of material will be hauled to the pile using either TCC's existing mobile <br />equipment fleet or contractor equipment. The original design of the Coal Refuse Pile was contracted to <br />CTL/Thompson. The design was revised and updated to reduce the overall footprint and address operational <br />placement concerns, by Northwest Colorado Consultants. Both the original design and revisions aze documented in <br />Exhibits 26-A and 26A-1. Within 30 days of start-up of the prepazation plant, a sample of the waste material <br />generated from the preparation plant was obtained and analyzed to verify the assumptions used for the pile design <br />presented in Exhibit 26A. TCC forwazded results of this analysis to the Division along with a certified statement <br />from a registered P.E. summarizing the results of the analyses as compared to the original design assumptions. The <br />surface runoff/diversion system design for the pile was developed in-house by TCC and is presented as Appendix D <br />to the CTL/Thompson Report. The locations of the Coal Refuse Pile and associated drainage features aze shown on <br />Map 24, Surface Facilities. <br />As shown on Exhibit 26A, Figure 1, the refuse pile is constructed west of the reclaimed valley to the west of the <br />Area 2 Pit. Prior to construction, approximately 18 inches of topsoil from within the pile footprint were removed <br />and placed in topsoil stockpile SF-12 (see Map 29}. During reclamation of completed pile benches, topsoil will be <br />redistributed over the face of the pile. Duect placement of topsoil will occur to the extent possible during the bench <br />reclamation/pile extension process. It is anticipated that topsoil replacement will stay one bench below the active <br />working zone of the pile. During construction of the refuse pile, inactive portions of topsoil stockpile SF-12 will be <br />seeded with the topsoil stabilization seed mixture at the fast appropriate opportunity following stockpiling <br />operations. Table 49A, Topsoil Stockpile Summary, has been revised to show the potential modification to the <br />existing stockpile SF-12 resulting from the construction of the refuse pile. Also, the table presents information for <br />all other topsoil stockpiles located at Twentymile. The stockpile identification correlates with the stockpiles <br />presented on Map 29. <br />Spoillsubsoil material will be used as the non-toxic cover to be placed over the coal refuse materials. During <br />development of the refuse pile, spoil/subsoil material will be selectively removed from within the footprint of the <br />pile. The spoil/subsoit will be hauled dvectly to the site and spread over the refuse material. After placement of <br />the spoil /subsoil material the area will be topsoiled as per the above. Redistributed topsoil will be seeded with the <br />pastureland seed mixture. <br />TR OS-47 2.05-96 Revised -January 2005 <br />