2021-09-07_REVISION - M1973021 (4)

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Aggregate Industries, Morrison Quarry Amendment No.7 to Permit M-1973-021 FYZ Morrison,CO Item 2.0 Project Safety Plan and Implementation The project will involve working around inactive quarry slopes and associated hazards, and the contractor must comply with applicable Mine Safety and Health Administration (MSHA) and Occupational Safety and Health Administration (OSHA) regulations. This task includes all of the operator and subcontractor's expenses for employee time, labor, materials, and safety equipment as well as safety training necessary for preparing and executing a job safety plan. Item 3.0 Erosion, Sedimentation, and Dust Control Plan This item covers the design, installation, maintenance, and removal of temporary erosion, sedimentation, and dust control features. The operator will be required to install these sediment control features prior to any ground-disturbing activities and maintain them throughout the duration of the reclamation project. The installed temporary erosion and sediment control features assume BMPs in accordance with the Site Stormwater Management Plan (SWMP), including but not limited to Site Grading, Earthen Berms, Stormwater Retention Ponds, Check Dams, and Truck Wheel Wash. Dust generated from the project area during work and off-work periods will be controlled and kept to a minimum. The operator will be required to develop and implement a Dust Control Plan, including BMPs and dust suppression of working areas during working and non-working periods, including weekends, throughout the duration of the project. Item 4.0 Site Survey This task consists of performing all surveys, measurements, and computations required by the specifications to accurately track that the materials are imported and exported according to the design drawings. Item 5.0 Dewatering To handle stormwater accumulations within the West and South Quarries (below El. 7,000 on the western wall), a horizontal drain will be installed running from the sump location of the South Quarry eastward and daylighting in either UD#2 or UD#3. Dewatering would consist of installing a borehole approximately 2,000 feet under the eastern wall of the South Quarry. The outlet of the borehole could consist of an 8-inch stainless steel standpipe to be able to handle up to 45 feet of head pressure. The remainder of the hole would be unlined and drilled at a 6.75-inch diameter, capable of handling up to 540 gallons per minute. It is assumed the outlet would be a free-flowing pipe, but if necessary, a wellhead complete with valve control and pressure gauge could be installed to regulate flows from the base of the South Quarry during heavy precipitation events. September 2021 1 33