2015-10-14_REVISION - C1981019 (2)

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Chris Gilbreath Page 6 Please update the text to ensure it is consistent sheets refers to Map 11B for cross-section locations. with the maps and figures submitted. Please show the locations of all geologic cross-sections on Map 7A. If the same figures are to be used in order to comply with rule 2.04.7 the cross section locations should also be shown on Map 10B. ITEM 66. The cross sections shown in Figure 2.04.6, Sheets 1 and 2 are drawn at a scale of 1” = 400’ (horizontal and vertical), with more than 70 stratigraphic layers. The scale makes it extremely difficult to Please redraw extract relevant information from the figures (particularly the thickness of the K layer). m the cross-sections with vertical exaggeration. A scale of 1” = 50’-100’ on the vertical axis would be appropriate. ITEM 67. The legend on Figure 2.04.6, Sheets 1 and 2, shows layers marked “Pit Shell”, “TCT” and “STCM” in addition to the 70+ identified coal seams. These layers appear not to have been drawn. Furthermore, it is not clear what “TCT” and “STCM” refer to. Per the text, the lowest coal seam to be mined is G which is shown in blue on the cross-sections. The Smectite layer (K), which has been Bm Please clarify the terms identified as a laterally continuous low-permeability layer, is shown in pink. used in the legend. Please also display the first aquifer below the lowest coal seam to be mined (presumably the Trout Creek Sandstone) on the cross-section. ITEM 68. In Volume 15, Rule 2, Page 13 the text reads “The Trout Creek sandstone underlies the lowest surface recoverable seam to be mined at South Taylor (the G seams) by approximately 590 feet”. 789 Please revise this section of text to refer to the separation between the Trout Creek sandstone and the lowest seam to be mined in the vicinity of the proposed Collom pit and use this value consistently throughout the text of volume 15. Please also cite the data that allows CCC to accurately assess the separation over this area. (Refer also to item 80 in this letter.) ITEM 69. In Volume 15, Rule 2, Page 16 a paragraph appears to have been inserted that is not relevant For clarity, to the Collom area: “Overburden and interburden samples from drill holes 97-06, 97-09 …”. please remove irrelevant text. ITEM 70. Of the six drill holes that were sampled for overburden/interburden analysis, only one falls within the 1.4 square mile (approximate) footprint of the newly proposed Collom pit (C-04-25). The guidelines call for a minimum of three sampling locations with a spacing of approximately one hole per square mile (from reference 1 below). In the geochemical analysis, CCC has also cited a guideline published by the Wyoming Department of Environmental Quality (from reference 2 below), which calls for an initial sample spacing of one hole per 80 acres (which is equivalent to eight holes per square mile). The geochemical data from the six holes is presented in Exhibit 6, Item 9, and summarized in table 2.04.6-7 and in the text. The data shows that hole C-04-25 contains a greater proportion of unsuitable overburden material than the other five holes. For example:  A significant proportion of the overburden sampled at this point (27%) contains Molybdenum at greater than 1 ppm.