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Groundwater Ouanti[y: Effect on the Colorado River Alluvial Aquifer <br />Water quantity in the alluvium of the Colorado River aquifer is minimally affected by [he mine <br />operations. The quantity of surface water and groundwater in the Roadside Nortft and South <br />Portal facility areas and adjacent areas will not be adversely affected due to the recycling nature. <br />of [he ground and surface waters in the alluvial valley floor. Since the mines are on ttte Colorado <br />River alluvial valley floor, the water pumped from the mines' old workings is essentially the <br />alluvial water already present in the river system. Additional water is added from the draining <br />of the coal aquifer as virgin coal seams are mined [o the south. Both waters are circulated <br />through the mine workings, thus accumulating solids and salts, before being discharged into the <br />Colorado River. Approximately 0.7 cfs of mine discharge water is removed from the <br />underground mine workings and allowed sufficient time to settle out the solids before being <br />discharged into the Colorado River. The salts cannot be filtered out using this method. The salt <br />loading result is discussed more thoroughly in the previous discussion regarding ground water <br />quality in the Colorado River alluvium. <br />III. Topsoil <br />Soils resource information found in Volume 2, Tab 9, and the topsoil salvage and redistribution plan <br />in Volumes 3 and 5, Tabs 13 and 14, of the application have been reviewed for compliance by the <br />Division. A discussion of issues raised during the PR-02 review is included in Section B, of this <br />document. <br />Since mining at this operation began prior to the Surface Mining Control and Reclamation Act, no <br />topsoil was salvaged in construction of the mine benches. Topsoil from the loadout area was used to <br />build the loadout stacker pad, although a small amount was stockpiled. The majority of the topsoil <br />salvaged was removed from the location of the Cameo refuse piles. <br />Soils in the general area are commonly high in sodium and occasionally saline. This is reflected in <br />the sparse vegetation which is primarily composed of salt-tolerant species and species such as <br />greasewood, which are commonly found growing in sodic soils. The analyses of the stockpiled soil <br />and the material presently on the surface of the disturbed areas reflect the saline and sodic conditions <br />of the surrounding area. <br />Upon completion of backfilling and grading operations, topsoil will be redistributed to a minimum <br />depth of six inches, with the exception of specified areas where topsoil was not salvaged originally. <br />These areas will be covered with a suitable amount of plant growth material and amended as <br />necessary. Prior to redistribution of the topsoil, the graded surface will be ripped to relieve <br />compaction and limit surface slippage. <br />Based on the results of a study conducted on the Roadside Refuse Disposal Area over a period of 10 <br />years, and associated physical and chemical analysis which demonstrated that requirements of Rule <br />4.15 can be met with less than four feet of cover material, the Division has approved a variance from <br />the four foot refuse cover depth requirement of Rule 4.10.4(5). Technical Revision 16, approved by <br />the Division in January, 1994, approved minimum cover replacement depths of 18" on the RSRDA, <br />CRDA-1 and CRDA-3, and a minimum of 24" on CRDA-2. Non-toxic cover borrow areas, and <br />topsoil and subsoil suitability levels and sampling plans were defined by TR-17, in April, 1994. <br />Reclamation of refuse areas will entail replacement of a minimum 6" topdressing layer with SAR of <br />36 <br />