Laserfiche WebLink
2.05 APPLICATION FOR PERMIT FOR SURFACE OR UNDERGROUND ACTIVITIES -- <br />MINIMUM REQUIREMENTS FOR OPERATION AND RECLAMATION PLANS. <br />2.05.6 Mitigation of Surface Coal Mining Operation Impacts. (cont'd.) <br />(3)(b)(ii) (Cont'd) <br />Two silt fences were installed on the slope as depicted on Map No. 8 -6. The Sedcad <br />demonstration for this area shows the silt fences were not necessary to meet water <br />quality standards. <br />2) Orchard Valley West Mine Fill (Northern Exposure) - consisted of approximately 0.8 <br />acres of revegetated disturbance comprised of the fill material and topsoil salvaged <br />during the construction of the West Mine portals (see Volume 8, Map No. 8 -6, and <br />Volume 8, pages SAE -11 thru SAE -15). Flow from this area was filtered by <br />vegetation established on the slope. The area supported a vigorous stand of grass <br />and forb species with cover conservatively estimated at 50 %. Grass filter model <br />inputs describing 3" spacing and 6" height were typically exceeded by the vegetation <br />at this location. No mixing of surface drainage and underground mine drainage <br />occurred within or resulted from this small area exemption. <br />The Sedcad modeling utilized to describe this site predicted runoff from the site <br />occurred in compliance with the allowable settleable solids concentration. <br />One silt fence was installed on this slope as depicted on Map No. 8 -6. The Sedcad <br />demonstration for this area shows that a silt fence was not necessary to meet water <br />quality standards. <br />3) Orchard Valley West Mine Vent Shaft & Fan Site - consisted of approximately 1.5 <br />acres of disturbance partially reclaimed (see Volume 8, Map No. 8 -7, and Volume <br />8, pages SAE -16 thru SAE -20). Runoff from the site was filtered through the <br />naturally occurring vegetative filter below the site. The vegetative filter area was <br />undisturbed and consisted primarily of dense oak, brush with grass understory, <br />and had accumulated a thick, nearly continuous layer of litter and detritus. Cover <br />in the vegetative filter area was conservatively estimated at 70 %. No mixing of <br />surface drainage and underground mine drainage occurred within or resulted <br />from this small area exemption. <br />The Sedcad modeling utilized to describe this site predicted runoff from the site <br />occurred in compliance with the allowable settleable solids concentration. <br />Removal of the silt fence installed below the disturbed area was approved by the <br />Division in May 1995. A combination berm rock filter was constructed immediately <br />below the fan area as depicted on Map 8 -7. <br />MR -132 -113a - 10/13 <br />:3D- OCR- l..l1 /3 <br />