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'~ Preliminary Adequacy Review <br />Bear Coal Co., Inc. - Bear Mine <br />Page Five <br />9 Ponds, Impoundments and <br />~~' Demonstrate how the statement that alteration of a natural drainage is "not <br />ariplicable" (page 62) while the plan labelled 2.04.3(2)(a)-1 shows a "permanent run- <br />r~ff diversion" with riprap (page 23). A detailed design of the permanent diversion <br />y a professional engineer must be supplied. The structure must be designed for the <br />100-year, 24-hour event pursuant to 4.05.9(2)(b) and 4.05.9(9). The sharp riyht <br />ngled turn in the diversion seems to compromise the intention of establishing a <br />natural post-mining configuration. The spoil pile North of the turn.in the diversion <br />ust be ad ion of the plan is warranted. 0 <br />MF~P ?~,04,3(2)(a)-1 <br />2. Sediment con ro system: Due to the short expected life of mine, problems noted <br />regarding sediment control design will be waived if an adequate maintenance plan <br />is supplied. The applicant should note that the highest sediment yield will be <br />' in the first phase of site reclamation. This may entail sediment removal more <br />than twice a year FIGURE 2,05,3(4)s-IE,5,6 <br />' a. 4.05.6(3)(b) Sediment clean out: The statement that sediment will be .removed <br />from the ponds on an annual basis will only be appropriate if the sediment volume <br />does not meet or exceed the pond's design capacity. A preferable maintenance <br />' schedule would call for removal of sediment. when the volume of sediment <br />accumulated equals some fraction of the design volume (say 60~). This must be <br />continued throughout reclamation phase of the operation. Ths Division suggests <br />the placement of permanent markers in each of the sediment ponds at the elevation <br />of the cleanout volume. This will assist mine and inspection personnel in pro- <br />viding for maintenance when necessary.. PAGE 64 <br />' F~C~~lRE 2.05.3(4)(A)(Iii)-1.2,3 <br />b. 4.05. )~(e)(i) Culverts: On page 62 of the application, BCC states that <br />two 16 inch culverts convey undisturbed drainage under the road and to the <br />river. These culverts should be displayed on some mine area map, peak flows <br />' for the 10-year, 24-hour event should be provided and calculations provided <br />to show that the culverts are adequate. <br />FIGURE 2,05,3(3)(c)(I) PAGE 62 <br />' c. 4.05.6(9) Design Drawings: BCC has not provided detailed design drawings <br />of any of the sediment control structures.' BCC must provide detailed design <br />drawings, including: <br />' 1) Embankment cross-sections showing: <br />I. Elevation of the 200 and cleanout sediment storage volumes. <br />' II. Elevation of the principal and emergency spillways and dewatering <br />devices. <br />2) Cross-section drawings of principal and emergency spillways. <br />3) Certification that the drawings were done by or under the supervision <br />of a Certified Professional Engineer. <br />DRAWING .2,05,3(4)($)-].A, 2A, 3A <br />1 <br />