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C. Sedimentation Ponds <br />Seneca Coal Company will primarily use sediment ponds to prevent additional <br />contributions of sediment to streamflow or runoff outside the permit area due to <br />mining disturbance. Existing sediment ponds include 005, 006, 009, 015, 016, <br />016A and 017. All sediment ponds that have been approved as of October <br />2004 have been constructed. Information regarding design of ponds and <br />diversions is provided in Tab 13 of the permit application. <br />Pond 005 was permitted as a permanent impoundment that treats runoff from 285.6 <br />disturbed acres which drain to Dry Creek. <br />Pond 006 was permitted as a permanent impoundment that is located in a watershed <br />that is tributary to Hubberson Gulch. The pond was constructed in five separate <br />phases as disturbance increased within the watershed. The final (Phase V) <br />design involved a 1.5 foot extension of the principal spillway riser, and <br />elimination of a "pre-settling basin° in the "B" Pit. Phase V spillway <br />modification was completed in August 2003 prior to "B" Pit bacltfilling. <br />Phase V "As-Built' Certification was completed in March 2004 and was <br />included in TR-48. <br />Pond 009, a temporary sediment pond, treats runoff from the smaller disturbed area <br />which drains to Sage Creek, roughly a 439 acre watershed. Construction of the <br />pond was completed in 1991. <br />Pond 015 was constructed during the summer of 1999 in preparation for <br />development in the Seneca II-W south extension area. The pond treats runoff from <br />a 407 acre watershed that drains into Sage Creek of which only 29.5 acres will be <br />disturbed by mining activities. <br />Pond 016 was constructed in the summer of 2000 in the Seneca II-W south <br />extension area. The pond treats runoff from 382.2 total acres. Discharge from this <br />pond goes into an unnamed tributary of Hubberson Gulch. <br />Pond 016A was constructed to provide sediment control for additional <br />disturbance approved in PR-3. Pond 016A is located in series immediately <br />up-gradient from Pond 016, on a Hubberson Gulch tributary. Embankment <br />and P.E. construction certification for Pond 016A was provided within TR- <br />48, in July 2004. Final certification of all aspects of pond construction was <br />delayed pending assessment and repair of in-slope slumps, which was <br />completed in September 2004. <br />Seneca II-W Findings Document 25 November 17, 2004 <br />Perini[ Revision No. 4 <br />