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2. 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 the <br />construction dirt storage azea and the office facility area. The operator has demonstrated <br />(Appendix M, pages M-5 through M-9) that the natural channel drainage will not be blocked, <br />no significant damage will occur to the hydrological balance, and no adverse impacts will <br />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 ditch to <br />the sedimentation pond, to ensure that all discharges meet effluent limits specified in the CDPS <br />discharge permit for the McClane Canyon Mine. The sediment pond was filled in with sediment <br />by a 100 year magnitude storm event in August 2001 that had buried and overwhehned one of the <br />primary upland diversion culverts. In association with excavation of sediment, the inside slopes of <br />the sediment pond were reduced to approximately 2H:1 V. The re-constructed pond was properly <br />certified by a professional engineer (see "Impoundment Yearly Inspection" of Mazch 29, 2002). <br />A storm water permit also dictates measures for ensuring that all surface runoff water leaving the <br />mine site meets applicable effluent limits. Three small disturbed areas; the office area, topsoil <br />stockpile, and construction dirt stockpile, aze not routed to a sediment pond, and aze approved as <br />small area exemptions (SAE'S). In these areas, sediment control is provided by diversion berms <br />and silt fencing demonstrated to be sufficient to ensure that runoff from the 10 year, 24-hour storm <br />event will meet the settleable solids dischazge limit of 0.5 mUl (Appendix pages M-2 through M- <br />4xxiii). The silt fences were approved within TR 11 to replace total containment sumps that had <br />previously provided sediment control for the small areas. The silt fencing was installed in 2002. <br />Mine water collected underground in sumps is authorized within the NPDES permit to be pumped <br />to the surface and directly discharged through a pipe to the McClane Drainage without being <br />routed through a sedimentation pond. Mine water discharges have been necessary on occasion <br />since resumption of operations in 2000, and the discharges have been in compliance with <br />applicable dischazge permit effluent limits. <br />Drainage and sediment control measures are addressed in Section 2.4.4 of the application text, as <br />well as various exhibits and appendices referenced in the text. Sections of the text and appendices <br />were amended to eliminate certain inconsistencies identified by the Division during the renewal <br />review. The following fording is made pursuant to the three small area exemptions referenced <br />above. <br />1. The Division proposes to grant small area exemptions (SAE'S) from use of sediment ponds <br />for the office facility azea (SAE-1, .78 acres), the topsoil stockpile (SAE-2, .39 acres), and <br />the construction dirt stockpile (SAE-3, .30 acres) due to the limited size of the areas and due <br />to the fact that the operator has demonstrated that ponds and treatment facilities aze not <br />necessary for the drainage to meet the eft7uent limitations of Rule 4.05.2 and applicable State <br />and Federal water quality standards for receiving streams, and also due to the fact that no <br />mixing of surface drainage with a dischazge from underground workings will occur <br />(4.05.2(3)(b)(i). <br />13 <br />