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PR-2 application. The narrative states that pit backfill azeas would be capped by at least <br />50 feet of material derived from truck-shovel operations, which remove overburden <br />located stratigraphically above the F6 coal seam. The only locations where deeper <br />(dragline handled) spoils between the F6 and G8 seams might end up on the surface <br />would be in the permanent valley fills. Narrative states that material placed in valley fills <br />will originate from the azea of the initial South Taylor boxcut. Narrative further states <br />that truck shovel overburden has been demonstrated to be suitable quality, and includes <br />documentation based on the relative thickness of unsuitable zones for pazameters of <br />potential concern, for the truck-shovel sequence, for five drill holes distributed across the <br />proposed South Taylor pit azea. Narrative further indicates that the drill holes <br />representative of the boxcut azea (presumably 83-D3-06, 83-D3-07, and 83-D3-10) show <br />no unsuitable material in the strata from the F6 seam down to the G8 seam, which would <br />be excavated by dragline. This was verified by review of the referenced bore holes. <br />From the information presented regazding the sequence of strata to be mined by the truck <br />shovel operation, one drill hole showed unsuitable SAR levels within strata comprising <br />approximately 15% of the sequence; unsuitable SAR levels were present in strata <br />representing 3% or less of the sequence in the remaining holes. Selenium levels greater <br />than 0.3 were present in strata representing approximately 3% of the sequence in one <br />hole, with mazginal values present in strata representing 2% or less of the sequence in the <br />remaining holes. Boron levels greater than 5.0 were present in strata representing <br />approximately 11 % of the sequence in one hole; with no strata having boron values <br />greater than 5.0 in the remaining holes. Saturation percentage was in the mazginal range <br />within strata representing 14% to 15% of the sequence in two holes; marginal values <br />were present in strata representing 3% or less of the sequence in the remaining holes. <br />Molybdenum values greater than 1.0 were present in strata representing between 3% and <br />7°l0 of the sequence in each hole. Based on the data presented, it would appear likely that <br />material mixing which will occur during truck-shovel handling will be adequate to <br />prevent the placement of spoil material with unsuitable chemical characteristics on the <br />surface. <br />The argument that material mixing during operational handling will result in dilution of <br />the relatively limited volumes of unsuitable material, and will ensure that ecologically <br />meaningful quantities of unsuitable spoil are not replaced in the root zone, is strongly <br />supported by regraded spoil monitoring data collected since the 1980's at Colowyo. This <br />data is referenced and summazized in the narrative of Section 2.04.6 of the PR-2 <br />application. <br />We have two remaining requests pursuant to this item. First, please include across- <br />reference to the regraded spoil monitoring summary assessment of Section 2.04.6, <br />within the relevant portion of Section 2.05.3(1). Second, please amend the List of <br />Tables on amended page v of the ST/LW table of contents to include Table 2.04.6-2. <br />2 <br />