2011-09-19_REVISION - M1982155 (17)

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Mining Methods Groundwater is not expected to be encountered during mining and the deposit will be dry mined. Mining will proceed by first stripping and stockpiling topsoils and overburden. The exposed gravel will then be removed in lifts and transported to the processing facility. Since the material is unconsolidated alluvium, no blasting is required. Earth Moving Areas to be mined are prepared by removal of topsoil and overburden. If mining includes Charter Oaks Ranch Road (Pre- Mining and Mining Plan Map — Option 2), the existing asphalt surface will be stripped and removed for recycling. Each preparation area may be as much as 100 feet wide. Usually, only enough area is stripped and prepared to provide the estimated needs for the next 10 to 14 months of mining. Where it is found, the upper four to seven inches of topsoil material will be stripped separate from the underlying, deeper subsoils. This topsoil layer contains most of the soils organic matter and will be stockpiled separately for use in reclamation. Once the surface layer has been removed, the rest of the overburden will be stripped and stockpiled separate from the surface layer. The upper layer of topsoil, although thin, is considerably darker than the lower layers of overburden. Inadvertent mixing of the topsoil layer with several inches of lower overburden layers will have little effect during the reclamation. However, blending all of the upper topsoil with the much greater volume of lower overburden could have a significant effect on reclamation success and, therefore, care will be taken to separate the upper topsoil layer. The active mining face will extend no more than 1,000 feet in length. During mining and prior to reclamation, the mine walls will be a nearly vertical to 1/2H:1 V slope (see Exhibit C -4, Pre - Mining and Mining Plan Map). Mining will progress down to the depth of quality aggregate material or 30 to 50 feet below the surface, whichever is encountered first. The aggregate material will be recovered using equipment typical for sand and gravel mining operations. Earth moving equipment may include, but are not limited to dozers, loaders, scrapers, and excavators. Field conveyors and watering trucks will be used as needed for mining operations and dust control. Setback areas from the mining excavation to the permit boundary will potentially be used for overburden stockpiles during mining. Setbacks will also be maintained for potential side slope reclamation if "cut and fill" sloping is required, as discussed further in Exhibit E, Reclamation Plan. The need for "cut and fill" reclamation will be determined during the mining operation once overburden quantities and general pit depth are determined. In the northern portions of the amendment area, where the pit depth will likely be its greatest, setbacks from the excavation to the permit boundary may be as much as 100 feet. Towards the southern end of the mining operation, however, the pit will become shallower and side slopes will steadily decrease in height, reducing potential setback distances. In addition to potential "cut and fill" reclamation needs, setbacks from near vertical mining excavations to the permit boundary will generally be twice the adjacent pit depth to mitigate stability risks. Fountain Pit M- 1982 -155 DRMS 112 Permit Amendment Page 7