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Chavers Mining Resource <br /> DRMS Permit No.M-2015-030 <br /> Amendment No.2(AM-02) <br /> January 2024 <br /> Page 7 <br /> materials are free of contaminants. All backfill materials will be inspected upon entry to <br /> the Site and while being unloaded using visual and/or olfactory methods to ensure no <br /> potentially contaminated materials are received. If evidence of possible contamination is <br /> observed, loads will be rejected and will not be allowed to be left on-site by the <br /> contractor. No contaminated materials will be accepted or allowed on-site.Any <br /> asphalt or concrete materials received will continue to be diverted to the recycled <br /> aggregate materials operation at the Site. <br /> ■ Backfilling Process: After an area of the property has been mined of sand and gravel, <br /> backfilling operations will begin once they can be safely conducted. ASCI will conduct <br /> backfill operations concurrent with mining operations whenever possible. The exposed <br /> pit area will constantly shift as concurrent mining and backfill operations occur, but <br /> ASCI will not exceed an exposed active mining and backfill pit area of approximately 20 <br /> acres at any one-time. The time to complete backfill will vary upon market conditions, <br /> but groundwater will continuously be pumped until backfill above static water level is <br /> complete. Backfill material will be imported to the Site with articulated dump trucks <br /> and/or highway dump trucks. The material will be placed and spread in one (1)to two <br /> (2)-foot lifts using haul trucks, bulldozers, excavators, and/or loaders. Compaction will <br /> take place during the filling process, as haul trucks and heavy equipment traverse over <br /> the fill. Temporary excavation slopes and temporary stockpiled material slopes may <br /> range from 1:1 to 3:1 depending on soil conditions in the mine. All slopes will be <br /> maintained for site safety and to minimize material erosion. Areas will be backfilled to a <br /> rough grade(i.e.,within approximately 2 - 3 feet of final grade). <br /> ■ Gradingand nd Topsoil: Once the backfill is near rough grade across the Site,the surface <br /> contours of the affected area will be graded to approximately twelve (12) inches below <br /> the final grade across the Site. After contour grading is complete, a minimum topsoil <br /> cover twelve (12) inches thick will be placed on top of the backfill to reach topographic <br /> elevations prior to mining(i.e., final grade). The final grade will control water runoff, <br /> erosion, and siltation to protect all areas outside the mine and allow surface drainage to <br /> flow gently as sheet flow to the northeast, consistent with pre-development drainage. <br /> To ensure grading requirements are met, elevations will be checked periodically by ASCI <br /> during the reclamation process. This will continue until the final grade is achieved with <br /> backfill materials and topsoil cover. A final topography survey will be conducted by <br /> ASCI after topsoil has been placed, but before seeding occurs to ensure that the Site <br /> topography is at pre-mining elevations and sloped for positive drainage. All surveys will <br /> be conducted by aerial drone. The allowable vertical variation will be approximately one <br /> (1) foot given that the final topography will be slightly undulating in areas to mimic the <br /> original landform. Once topography across the Site is within acceptable limits,ASCI will <br />