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Section 3 <br />Conclusions and Recommendations <br />Additional drainage control structures are necessary to route offsite surface flow <br />around the surface mine area and retain the 100-year, 24-hr storm event within the <br />onsite berms. CDM recommends the following for Van 4 Mine storm water drainage <br />control: <br />1. Inspect the existing roadside channel along the north side of County Road DD19 <br />to confirm that the depth of this ditch is greater than or equal to 3.5 feet and the <br />side slope of this ditch is milder than or equal to 3H:1V. If the minimum channel <br />criteria are not met, complete channel improvements to satisfy the configuration <br />as illustrated in Exhibit A. <br />2. Inspect the existing berm enclosing Basin 2 to confirm that the minimum height of <br />the existing berm is 1.5 feet and that the berm completely encloses the retention <br />area illustrated in Exhibits A and B. If the minimum berm criteria are not met, <br />complete berm improvements to satisfy the configuration as illustrated in Exhibits <br />A and B. <br />3. Inspect the existing berm (water bar) enclosing Basin 3 to confirm that the <br />minimum height of the existing berm is 1.5 feet and that the berm completely <br />encloses the retention area illustrated in Exhibits A and B. If the minimum berm <br />criteria are not met, complete berm improvements to satisfy the configuration as <br />illustrated in Exhibits A and B. <br />A plan view and details of the proposed diversion channel and berms are included in <br />Exhibits A and B. <br />F - <br />3-1 <br />7184886-Denison Mines\Task Order 1 - Sunday Mines Drainage SWdoVan 4 Mine Drainage SludVkReporWan4 Mine Drainage Report_final.docx