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As a result of using the CDRMS suggested values, some minor text edits to <br />page 16 of the Application for Phase I and II Bond Release were made, and <br />the updated page has been enclosed, along with the updated Table 4. <br />6. Based on the information in the discussion above, please revise the conservation <br />practice factor, the "P" factor, in Table 4 for the post- mining conditions. Please <br />use site - specific information to justify the "P" factor. Please recalculate the <br />average annual soil loss in RUSLE using the new "P" factor. Please provide the <br />Division with the revised pages in Section 4 of SL -04 justifying the "P" factor and <br />please provide and updated Table 4 with the new "P" factor and revised soil loss <br />calculations. <br />Colowyo Response: The rationale for selecting practice factor "P" is <br />similar to the above discussion relating to cover practice "C ". The end <br />result is that adopting CDRMS' suggested value of 0.9 for the reclaimed <br />condition, essentially the same value as was selected of pre- mining <br />condition, in conjunction with the revised values for the cover practice <br />factor "C" described in response to Comment 5, does not change the <br />conclusion that the reclaimed lands produce somewhat less sediment than <br />the pre -mine lands. This issue is therefore also academic for this filing. <br />Colowyo based its original selection of the practice factor "P" on Figure 6 -2 <br />of USDA Agricultural Handbook No. 703, which figure relates the factor "P" <br />to rill depth and slope. Because the evidence of contour plowing and <br />seeding is evident on the current airphotos several years after seeding is <br />complete, Colowyo feel that remnants of the original rills are in place even <br />though no active management has been carried out after initial seeding. <br />Colowyo assumed the surviving rills are on the order of 4 to 6 inches, and <br />entered Figure 6 -2 with the average slope for each identified sub -area to <br />arrive at a subarea - specific "P ". The average arrived at in this manner was <br />0.53, which is considerably less than the `pre- mining" value of 0.9 but <br />greater than the nominal value of 0.38 approved in TR -73. <br />However, as noted above, when replacing the "P" factor calculated as <br />described above with a default value of 0.9 as suggested by CDRMS, the <br />resulting estimated yield does not change the conclusion that the reclaimed <br />lands do not produce more sediment than the pre- mining condition. <br />Colowyo therefore view has incorporated CDRMS suggested value of 0.9, <br />the same as pre- mining, into the revised Table 4. <br />As a result of using the CDRMS suggested values, some minor text edits to <br />page 16 of the Application for Phase I and II Bond Release were made, and <br />the updated page has been enclosed, along with the updated Table 4. <br />