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will have an approximate six-inch thick fine gravel-surfaced wearing course over approximately <br />nine inches of coarse crushed rock, which will in turn sit on approximately 18 inches of compacted <br />aggregate base over the native subgrade. Haul roads will generally be at least 60 feet in width to <br />provide ample room for vehicles to safely pass each other. Maximum grades on the haul roads will <br />generally be 10-percent or less, and roads will be designed with a 2-percent cross fall to facilitate <br />drainage. Horizontal curves will generally be designed with a radius of at least 150 feet and will <br />be designed with approximately 10-percent superelevation to safely accommodate anticipated <br />travel speeds. Vertical curves will be flat enough to allow for safe braking distances by loaded haul <br />trucks to avoid obstruction in the travel way. A drainage ditch will run along the downhill side of <br />the haul road, and haul roads will be bordered by berms, the height of which will be at least as <br />high as the axle on the largest piece of equipment expected to use the road. Haul roads will be <br />watered as needed to control dust, and will also be treated with a chemical dust suppressant such <br />as calcium or magnesium chloride. A typical haul road cross section is shown on Figure 1. A <br />conveyor may be installed to transport material from the Mineral Materials Sale Area to the <br />processing area on Martin Marietta-owned property. The proposed conveyor route will generally <br />run north-south and will follow the natural topography outside of the mining area. Conveyor <br />supports will not be placed within designated waterways. <br /> <br />4. Bench Design <br /> <br />Two types of mining benches will be created during the mining process, production benches and <br />reclamation benches. The production benches are those created during the active mining process, <br />the face of which is the source of the mined materials. Reclamation benches are those which remain <br />when mining is completed, and are generally located at the mining disturbance boundary. <br />Production benches will not exceed 60 feet in height, have a face angle anticipated to be <br />approximately 80 degrees, and a width of not less than 40 feet. Temporary safety berms will be <br />constructed parallel to and at the top edge, and ten feet from the base of production benches that <br />are not actively being mined. Reclamation benches will typically be approximately 35 feet high, <br />have a bench width of approximately 30 feet, and a face angle of approximately 80 degrees, <br />resulting in an overall approximate 1:1 (horizontal to vertical) reclamation slope. However, some <br />reclamation benches may be left taller to enhance wildlife habitat. The actual bench geometry <br />selected will be that which provides a minimum static factor of safety of 1.3, based on rock slope <br />stability analysis. Cross-sections of typical production and reclamation benches are shown in <br />Figure 2. <br /> <br />5. Material Handling – Alluvial Quarry <br /> <br />The alluvial deposit on the site is mostly mined out, with only residual material available. <br />However, limited mining of the residual alluvial material may continue. Mining of the alluvial <br />materials will be conducted using the excavation techniques approved in the original mine permit <br />and the 2008 mine plan amendment. <br /> <br />6. Materials Handling – Granite Quarry <br /> <br />Overburden and topsoil will be stripped from areas to be mined by the use of conventional heavy <br />earthmoving equipment. Overburden and topsoil will be placed in stockpiles for reuse during the