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2.05 APPISCATION E'OI2 PFRt~II'P E'CHt SURFACE OR t1NDERGROtR~ID MINING ACTIVITIES - <br />MINII~IUM REQUIRII~lTS E'OI2 OPERATION AND RDCLAMF.TIC~I PIdiNS. <br />2.05.6 Mitigation of Surface Coal Mininq Operation Facts. (Cont'd.) <br />(3) (b) (ii) (A & B) (Cont'd.) <br />In most cases no treatment other than a 24-hour detention time, allowing sediment <br />to settle out, is needed for discharges from Pond #4 or COVCC's other NPDFS <br />discharge points to meet state and federal water quality standards. Should <br />treatment be necessary, the water may be retained in the ponds and material, such <br />as flocculent, added to bring the discharge into compliance with NPDES <br />requirements. Water which is discharged from Pond #4 or other COVCC NPDFS <br />discharge points is sampled and sent for laboratory analysis. Reports are <br />submitted quarterly to the regulatory authority. See NPDES Appendix in Volume <br />SA for specific information on NPDES requirements. <br />Small Area EScemptions <br />As stipulated in Rule 4.05.2 (3) (a) (b) the Division may grant exemptions from Rule <br />4.05.2(1) which states "All surface drainage from the disturbed area, including <br />disturbed areas that have been graded, seeded, or planted, shall be passed <br />through a sedimentation pond, a series of sedimentation ponds, or a treatment <br />facility before leaving the permit area." If the operator demonstrates that <br />sedimentation ponds are not necessary for the drainage to meet the effluent <br />limitation of 4.05.2 and if the disturbed surface drainage area within the total <br />disturbed surface area is small, the exemption may be given. <br />Cyprus Orchard Valley Coal Corporation (COVCC) has several areas which fall <br />within the guidelines of rule 4.05.2(3)(a)(b). These are described below: <br />•~ 1) Orchard Valley West Mine Fill (Southern EJtposure) -consisting of <br />approximately 2.3 acres of revegetated disturbance cong~rised of the <br />fill material and topsoil salvaged during the construction of the <br />West Mine portals (see Volume 8, Map No. 8-6, and Volume 8, pages <br />SAE-1 thru SAE-10). Runoff from this area is directed through two <br />grass filters. One located on the terrace midway down the slope, <br />and one located at the toe of the slope. The areas designated as <br />grass filter were revegetated in 1987 with the permanent seed <br />mixture utilized at Orchard Valley. The areas currently support <br />vigorous stands of grass and forb species with cover conservatively <br />estimated at 50%. Grass filter model inputs describing 3" spacing <br />and 6" height are typically exceeded by the vegetation at this <br />location. <br />The Sedcad modelling utilized to describe this site predicts runoff <br />from the site will occur in compliance with the allowable settleable <br />solids concentration. No mixing of surface drainage and underground <br />mine drainage occurs within or results from this small area <br />exenq~tion. <br />Two silt fences are installed on this slope as depicted on Map No. <br />8-6. The Sedcad demonstration for this area shows that the silt <br />fences are not necessary to meet water quality standards. However, <br />until such time as the Division approves their removal, the silt <br />fences will be examined periodically and maintained to ensure <br />adequate function at all times. <br />2) Orchard Valley West Mine Fill (Northern Exposure) -consisting of <br />TR 92-20 Revised 11/20/92 <br />113 <br />