2019-07-09_REVISION - M2004044 (32)

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EXHIBIT L Reclamation Costs To calculate maximum potential reclamation liability, we have selected a point in time where reclamation costs could be at a maximum. It is assumed that the time of maximum mining disturbance will be at the end of mining in the East cell (Phase 3). During this scenario, the slurry wall has been installed around the East mining cell and mining is complete in the South cell,the South cell is partially backfilled with material generated by the mining in the east cell. The existing pond located outside the slurry wall has been backfilled with material generated from mining in the East cell and revegetated. Most of the East cell slopes have been graded with overburden material stripped from the active mining areas. The active mining area includes a portion of the East mining cell and the working face of the East cell. In front of the active mining face, an area approximately 100 feet wide by 800 feet long will have been pre-stripped in anticipation of mining (2 acres). The pre-stripped area receives topsoil placement, final grading, and seeding for revegetation. The mining highwall is approximately 800 feet long and adjacent 1,500-foot long cell walls have not yet been backfilled. Both the mining highwall and adjacent cell walls (2,300 linear feet total) will be backfilled and rough graded to 3HAV slopes (assume move 1-foot of material over entire grading area) in preparation for topsoil placement, final grading, and seeding for revegetation. Material stockpiles will be located on the floor of the East cell. Haul distances to use the stockpiled topsoil will average about 300 feet. Miscellaneous disturbed areas at the point of maximum disturbance will include internal haul roads and the main site access road (3 acres), and stockpile areas (5 acres) and the conveyor route (3.3 acres). These areas will be tilled in preparation for topsoil placement, final grading, and seeding for revegetation. In addition, the South Cell is partially backfilled and will need the remaining backfill, placement of topsoil and seeding. It is estimated that the combined area disturbances will be approximately 88 acres. A minimum of 6 to 12 inches of topsoil or growth medium will be placed on all disturbed areas following backfilling, scarifying, and/or rough grading. Enough topsoil will be stockpiled on-site for reclamation. Final grading of the topsoil/growth medium is assumed to move one foot of material over the entire grading area and will prepare the surface for seeding. After initial seeding and the first season's growth, it is estimated that approximately 20 percent of the seeded area will need to be re-seeded. Each aspect is listed in the following table with associated disturbed area. Since all structures used in the mining operation are portable, it is assumed that removal of the structures does not have associated costs. Aggregate Industries Tucson South Resource Permit#M-2004-044 112 Permit Amendment Page L-1