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RULE 2 PERMITS <br />overburden into the previously mined-out pit. The "E" and "F" overburden is removed <br />from the spoil side of the pit. The spoil from the benching operation will be placed to <br />allow the draglines sufficient room and adequate reach to remove overburden while <br />operating on the spoil side. The draglines construct temporary ramps in order to walk to <br />the spoil side. <br />The "B" overburden is first drilled and blasted, removed by the draglines, "B" coal is <br />removed behind the advance of the draglines, then the drilling is initiated on the <br />overburden of the "C" seam. This sequence is typical through the "F" seam. <br />Upon complete removal of the overburden over the "F" seam, the draglines walk around <br />the end of the pit to the next cut to begin removal of the overburden over "B" coal seam. <br />Overburden Monitoring Program <br />Historically, beginning around 1983, Colowyo initiated overburden monitoring in both the pit <br />(truck/shovel materials) and on regraded overburden. See CDRMS Permit Exhibit 6, Item 4 as described <br />in the associated January 4, 1983 Colowyo memo to Dan Mathews, CDRMS, for an overview of this <br />initial program. Starting in 1990, Colowyo eliminated the in-pit sampling program. Sufficient data had <br />been collected to indicate that all weathered overburden material (ie within - 50 fee of the ground <br />surface) was suitable for replacement onto the reclaimed surface prior to topsoil replacement. Three <br />revisions were submitted to the Division and approved on January 24, 1984, August 17, 1983, April 24, <br />1990, and PR-02 respectively. The following summarizes the requirements of the current regraded <br />overburden (backfill) sampling program and supersedes all previous commitments. It is based on the <br />following limitations of the earlier program. <br />Placing weathered overburden material onto reclamation areas prior to final regarding, and <br />Sampling regraded overburden at a density of one composite surface sample per 5 acres of <br />regraded spoil. <br />The regarding of overburden is an event that tak3es place sporadically during the year. Once backfill <br />areas are regraded, but prior to topsoil replacement, the new locations are identified and sampled. A life- <br />of-mine sampling grid has been established on 500-foot centers, and each sample location on the grid <br />corresponds to a letter/number combination as established on the sampling map. Using this grid interval, <br />each sample location represents an areas of about 5.7 acres in size. A hand shovel is used to take small, <br />representative surface samples of spoil across the sample area. <br />Regraded Overburden Suspect Levels: <br />Parameter Suspect Level <br />H Less than 5 or greater than 9 standard units <br />Electrical Conductivity Greater than 12 millimhos/cm <br />Sodium Absorption Ratio Greater than 15 <br />The laboratory results are kept at the mine site. Results of the sampling program are provided in the <br />appropriate Annual Reclamation Report and are periodically checked during CDRMS quarterly complete <br />inspections. <br />If the results of the sampling indicate that one or more of the parameter suspect levels is reached, the <br />Division will be contacted. At that point, Colowyo, will resample the area to determine the extent of the <br />Rule 2 Permits 2.05-3 Revision Date: 6/23/08 <br />Revision No.: MR-91