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There would appear to have been no appreciable benefit gained from using some <br />combination of available topsoil stockpiles for topdressing, as opposed to use of the CBA- <br />2 borrow material. (Topsoil Pile 1 was marginally higher quality, but use of Topsoil Pile 1 <br />would have "robbed" the material from the North Portal Reclamation project, and various <br />other areas to be reclaimed). Original pemrit projections regarding the availability of <br />sufficient material meeting "topsoil" criteria within approved stockpiles and designated <br />borrow aeeas in the vicinity of the North Portal and CRDA refuse areas were appazently <br />erroneous. <br />RSRDA <br />Roadside borrow azea pre-salvage soils data indicated comparatively high quality soils, <br />with al] 16 sampled zones meeting subsoil quality criteria for both EC and SAR, and only <br />4 of the 16 mazginally exceeding quality criteria for topsoil. Average values fox EC and <br />SAR were well below the permit specified criteria for topsoil. Re-spread sample data <br />verify the generally high quality of the salvaged soils; EC and SAR levels were lower than <br />the topsoil quality threshold in all 11 samples. <br />Based on review of the information provided, the Division concludes that permit compliance was <br />demonstrated for CRDA-2 subsoil quality, CRDA-1 subsoil quality, and RSRDA subsoil and topsoil <br />quality. Quality of topdressing material was mazginal on CRDA-2, and did not meet the suitability <br />criteria on CRDA-1. <br />Should observation and monitoring of vegetative development on the refuse piles indicate <br />problems potentially attributable to high levels of salinity or sodium in the surface soils (e.g. <br />significant baze aeeas or stunted vegetation out of character with the native environment), <br />appropriate assessment and mitigative measures will be required. <br />N. Sealine of Drilled Holes and Under round Openings <br />The method for sealing portals is depicted in Permit Figure 14-2. The South Mine Portals have been <br />sealed with a 24" thick concrete seal, and will be backfilled with approximately 100 feet of dirt <br />backfill extending out from the concrete seals. An underdrain will be installed in conjunction with <br />final backfilling to drain portal area seepage away from the portal backfill. Other mine azea portal <br />openings were backfilled with a minimum of 25 feet of incombustible backfill. Long term mine <br />dischazge (post reclamation) from the Roadside South Mine will be from a gravity dischazge pipe <br />installed by angled drilling in the vicinity of the North Decline azea (Outfa11016); a back-up discharge <br />system is provided by a portal drain installed in the seal of the reclaimed Northwest Intake Portal, <br />which allows dischazge through CDPS Outfall #002 via siphon tubes. Outfall 002 would only be used <br />in the event of malfunction of Outfa11016. Due to the orientation of the North Mine workings, which <br />slope away from the portal and river, and due to the elevation of the portal which is above the <br />recovered goundwater elevation, no surface dischazge from the North Portal Mine is projected <br />following reclamation, and thus no provisions were made for dischazge from the North Mine following <br />reclamation. <br />37 <br />