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<br />„~2. The Division was concerned that the vegetation sampling <br />locations may not have been representative of certain areas of <br />the mine site and, therefore, some of the curve numbers used <br />for hydrology analyses may be too low. BRL responded that the <br />vegetation sampling locations were considered specifically for <br />determination of revegetation success, not necessarily for <br />determination of curve numbers. <br />The Division understands that the vegetation monitoring <br />locations were not necessarily considered for use in the <br />determination of curve numbers. However, the vegetation data <br />is being used that way, as evidenced in Exhibit 8. Please <br />provide evidence that the vegetation data used in Exhibit 8 <br />provides a reasonable curve number for those drainage areas <br />that were not the specific sites used for the vegetation <br />sampling. <br />x/53. The Division has no further concerns. The annotation for the <br />gob pile pond was added to revised Map 20, Sedimentation <br />Control Plan, and revised Map 21-1, Drainage Plans. <br />54. The Division questioned whether pond A was a dugout pond and, <br />therefore, whether the pond outslope of 1.5H:1.OV was out of <br />compliance. BRL stated that it considered pond A to be a <br />dugout pond, but, nonetheless, considered the effective slope <br />to be in compliance. BRL provided a revised Map 22-A. <br />I/ 55. The Division has no further concerns. BRL pointed out that the <br />VVV hydrology designs in Appendix B are of a general nature only. <br />Further refinements of those designs appear in Appendix C, and <br />constitute the in-the-field structure designs that are shown <br />on brawings 95266-02 and 95266-04. <br />x/56. The Division has no further concerns. BRL supplied revised <br />pages for Appendix B and Appendix C that show that all ditches <br />will have sideslopes of 2H:1V. <br />J 57. The Division has no further concerns. BRL submitted a revised <br />"minimum spillway requirements" worksheet for the coal mine <br />waste bank pond. The design for the spillway is shown on <br />Drawing 95266-04 and the dimensions are larger than the <br />minimum requirements. <br />1 58. The Division has no further concerns. The Division wanted BRL <br />to justify a curve number of 63 for the waste bank drainage <br />area A3 b, rather than using a curve number of 83. BRL decided <br />to redesign the drainage area for the waste bank, using amore <br />realistic senario. A curve number of 90 was used for exposed <br />coal waste and a Curve number of80 was used for reclaimed <br />areas. <br />5 <br />