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<br /> <br /> <br /> 20 <br />ditches have been approved but not constructed. All ditches will be seeded to <br />establish vegetation to reduce velocities and thereby prevent erosion and additional <br />contributions of sediment. When no longer needed, the ditches will be reclaimed <br />and the culverts removed. Design information for the ditches and culverts is located <br />in Section 2.05.3(4) of the permit application package. The location of the diversion <br />ditches and culverts are shown on Maps 2.05.3(3)-3, 2.05.3(4)-7 and 2.05.3(4)-9 of <br />the permit. ERMR does not propose any clean water diversions away from the <br />disturbed areas (4.05.3(1)). <br /> <br /> C. Stream Channel Diversions <br /> <br />ERMR has not proposed stream channel diversions at NHN. The three draws within <br />the permit area are Nygren, Meehan, and Glasier. <br /> <br /> D. Sedimentation Ponds <br /> <br />Two sedimentation ponds have been constructed, and a third is approved to be <br />constructed, within the permit area to treat runoff from all disturbed areas. The <br />capacity of the ponds will be achieved with a combination of partial excavation <br />below grade and constructed embankments. Pond NHN-001 has been constructed <br />along the southern permit boundary, Pond NHN-002 is centrally located north/south <br />along the western boundary, and Pond NHN-003 is approved to be constructed in <br />the northwest corner of the permit area. The design information for the <br />sedimentation ponds is located in Section 2.05.3(4) of the permit application <br />package, and the locations of the sedimentation ponds are shown on Map 2.05.3(4)- <br />1 of the permit application package. <br /> <br />1. None of the three sediment ponds is approved to be located within a perennial <br />stream (4.05.6(1)(b)). <br /> <br />2. Alternative design criteria and specifications have not been proposed for use <br />in sediment pond design and/or construction (4.05.6(11)). <br /> <br /> E. Acid-forming and Toxic-forming Spoil <br /> <br />The Division proposes to re-approve temporary storage of acid- and toxic forming <br />spoil for more than 30 days. This decision is based on a finding that burial or <br />treatment of these materials within 30 days is not feasible and the delay will not <br />result in any material risk of water pollution or other environmental damage <br />(4.05.8(3)). See Section 2.04.6 for identification, mining plan contingencies, and <br />physical/chemical properties of the overburden. ERMR has developed plans for <br />sampling overburden during mining to identify the quantity and quality of <br />deleterious material. Spoil and mine soil reconstruction plans that address acid and <br />toxic-forming materials in the NHN permit area is given in Section 2.05.4(2)(d). <br /> <br /> F. Impoundments