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The Division proposes to approve the alteration or relocation of a natural channel <br />drainageway located on the lower segment of McClane Canyon drainage, between <br />the riprap storage area and the office facility area, subject to Stipulation No. 25, <br />which requves the applicant to demonstrate that the natural channel drainage will <br />not be blocked, no significant damage will occur to the hydrological balance, and <br />no adverse impacts will occur to adjoining landowners (4.03.1(4)(a)(i)). <br />II. HYDROLOGIC BALANCE -Rule 4.05 <br />A. Water Quality Standards and Effluent Limitations <br />All surface drainage from the mine bench/face-up area is directed via the road drainage <br />ditch to the sedimentation pond, to ensure that all discharges meet effluent limits in <br />GVCC's NPDES permit for the McClane Canyon Mine. A storm water permit also <br />dictates measures for ensuring that all surface runoff water leaving the mine site meets <br />applicable effluent limits. Three small disturbed areas; the office area, topsoil stockpile, <br />and riprap stockpile, are not routed to a sediment pond, and are approved as small area <br />exemptions (SAE'S). In these areas, sediment control is provided by diversion berms <br />and sediment traps sized to contain the runoff from the 25-year, 24-hour storm event. <br />Mine water collected underground in sumps is authorized within the NPDES permit to <br />be pumped to the surface and duectly discharged through a pipe to the McClane <br />Drainage without being routed through a sedimentation pond. Mine water discharges <br />have not occurred since ] 990, but discharges which did occur in the past were in <br />compliance with applicable discharge permit effluent limits. <br />Drainage and sediment control measures are addressed in Section 2.4.4 of the <br />application text, as well as various exhibits and appendices referenced in the text. <br />Sections of the text and appendices were amended to eliminate certain inconsistencies <br />identified by the Division during the renewal review. The following finding is made <br />pursuant to the three small area exemptions referenced above. <br />The Division proposes to grant small area exemptions (SAE'S) from use of <br />sediment ponds for the office facility area (SAE-l, .33 acres disturbed), the topsoil <br />stockpile (SAE-2, .39 acres disturbed), and the rip-rap stockpile (SAE-3, .30 acres <br />disturbed) due to the limited size of the areas and due to the fact that GVCC has <br />demonstrated that ponds and treatment facilities are not necessary for the drainage <br />to meet the effluent limitations of Rule 4.05.2 and applicable State and Federal <br />water quality standards for receiving streams and also due to the fact that no <br />mixing of surface drainage with a discharge from underground workings will occur <br />(4.05.2(3)(b)(i). <br />B. Diversions, Conveyance of Overland Flow, and Stream Channel Diversions <br />14 <br />