2016-05-05_REVISION - C1981019 (3)

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Rob Zuber Page 3 May 5, 2016 MLC -04-01 is a currently approved monitoring point, which exists on the ground. With the approval of PR -04 it will be replaced with MLC -04-02 (which has not yet been drilled). The Response is sufficient. b. Is completion information available for MJ -95-02, UL -95-01 and C-04-1613? If so, please add it to the PAP. Completion diagrams for MJ -95-02, UL -95-01 and C -04-16B were added to Exhibit 7 Item 21A. The response is sufficient. 76. The response is sufficient. 77. The text in Volume 15, Rule 2, Page 22, also describes potentiometric head values at several points in the Trout Creek Sandstone. It is not clear from the material that has been submitted how well characterized the potentiometric surface in the Trout Creek Sandstone is in the vicinity of the proposed Collom pit. Such characterization of the baseline conditions will allow an assessment of the veracity of the Probable Hydrologic Consequences (PHC) later in the life of the permitted operation. Please project the baseline potentiometric surface in the Trout Creek Sandstone over the Colowyo permit area, including the proposed Collom expansion, onto a map (possibly Map 1013). The map should identify the points that were used in the projection. Depending on seasonal variability, it may be appropriate to show a maximum and minimum projected surface. If CCC has already addressed this characterization through previous mapping or modeling work please direct DRMS to the appropriate documentation. CCC responded that Map 10B had been updated with the projected potentiometric surface of the Trout Creek Sandstone, and that the text had been inserted into Volume 15, Rule 2 to discuss the wells that were used to determine the surface. Contour lines at intervals of 100', from 6600' to 6800', were projected onto Map 1013. They indicate that the hydraulic gradient is such that groundwater would flow in in south-westerly direction. The text on proposed Page 23 indicates that 5 points were considered in the determination of this surface (C-05-33, DH -76-8, W-95-02, W-95-15 and UL -95-45). Of these, C- 05-33 and DH -76-8 were rightly discarded since they were dry and uncased respectively. Several issues are evident: (1) W-95-15 is not shown on Map 106; (2) There is potential confusion over the location of W-95-02, since another point (also in the Wilson Creek drainage) is labeled MW -95-02; (3) considering just UL -95-45 and W-95-02, since the location of W-95-15 isn't shown, the potentiometric gradient is in the direction of W-95-02, (based on the data