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Colowyo, C3981 -019, PR3 adequacy No. 3 21 July 22, 2011 <br />Please use in the calculations a hydraulic gradient of 0.1 ft/ft, based on a representative 6- <br />degree bedding plane dip in the area (hydraulic gradient = tangent of 6 degrees = 0.1). <br />The response is adequate. <br />2. Please revise the prediction of spoil spring discharges to the surface (Section 2.05.6(3)(b(iii)) to <br />reflect the requested calculations of annual pitwall seepage. <br />As previously requested, please add to the analysis (currently on page 133) a calculation of <br />annual pitwall seepage at the downdip end of Cullom Lite Pit. In the analysis, please predict <br />the spoil spring discharge rate by subtracting pihvall seepage from pit inflow. This method of <br />nnulvsis is shown at the end of the attached Exhibit A. <br />Rule 2.06.8 Alluvial Valley Floor Determination <br />1. Significant reference to Dames and Moore (1980, 1995) and Walsh (1984) studies regarding <br />Alluvial Valley Floor investigations are found within Permit Revision No. 3. Efforts to find <br />these studies in the original Colowyo permit have however been unsuccessful. Please re- <br />submit the Dames and Moore (1980, 1995) and Walsh (1984) studies or reference where in the <br />existing permit they are located. <br />CCC's response is adequate. <br />2. The last paragraph, page 6 in Exhibit 7, Item 24 says that "final conclusions will be presented <br />following our review of the data remaining to be collected ". Maxim compiled this document in <br />September of 2005; has more data been collected since then? If so, please provide that data. <br />CCC's response is adequate. <br />3. Referring to Table 1 in Exhibit 1, Item 24, the West Jubb Drainage Alluvial Monitoring Well is <br />labeled MJ 95 -01 and on the Map (Figurel) Valley Fill Deposits. The East Jubb Drainage is <br />labeled MJ 95 -02 on Figure 1, but in Table 1 is called West Jubb. Please change the name of <br />the drainage in Table 1 to East Jubb for Well ID MJ 95 -02. <br />CCC's response is adequate. <br />4. Sections of Collom Gulch have been previously identified by the Office of Surface Mining as <br />potentially irrigable based on water availability sufficient for irrigation development consistent <br />with regional agricultural practices. Although Maxim referenced this OSM 1985 <br />Reconnaissance Map to assist in Alluvial Valley Floors, they do not go into great detail about <br />Collura. Gulch and its potential to be an alluvial valley floor downstream. Please amend the <br />text with more discussion of Collom Gulch, specifically a discussion on the value to <br />landowners downstream. <br />CCC's response is adequate. <br />