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Mining Methods <br />Groundwater is not expected to be encountered during mining and the deposit will be dry mined. <br />Mining will proceed by first stripping and stockpiling topsoils and overburden. The exposed <br />gravel will then be removed in lifts and transported to the processing facility. Since the material <br />is unconsolidated alluvium, no blasting is required. <br />Earth Moving <br />Areas to be mined are prepared by removal of topsoil and overburden. During the mining of <br />material under Charter Oaks Ranch Road the existing asphalt surface will be stripped and <br />removed for recycling. Each preparation area may be as much as 100 feet wide. Usually, only <br />enough area is stripped and prepared to provide the estimated needs for the next 10 to 14 months <br />of mining. <br />Where it is found, the upper four to seven inches of topsoil material will be stripped separate <br />from the underlying, deeper subsoils. This topsoil layer contains most of the soils organic matter <br />and will be stockpiled separately for use in reclamation. Once the surface layer has been <br />removed, the rest of the overburden will be stripped and stockpiled separate from the surface <br />layer. The upper layer of topsoil, although thin, is considerably darker than the lower layers of <br />overburden. Inadvertent mixing of the topsoil layer with several inches of lower overburden <br />layers will have little effect during the reclamation. However, blending all of the upper topsoil <br />with the much greater volume of lower overburden could have a significant effect on reclamation <br />success and, therefore, care will be taken to separate the upper topsoil layer. <br />The active mining face will extend no more than 1,000 feet in length. During mining and prior <br />to reclamation, the mine walls will be a nearly vertical to 1/2H:1 V slope (see Exhibit C -4, Pre - <br />Mining and Mining Plan Map). Mining will progress down to the depth of quality aggregate <br />material or 30 to 50 feet below the surface, whichever is encountered first. The aggregate <br />material will be recovered using equipment typical for sand and gravel mining operations. Earth <br />moving equipment may include, but are not limited to dozers, loaders, scrapers, and excavators. <br />Watering trucks will be used as needed for mining operations and dust control. <br />Setback areas from the mining excavation to the permit boundary will potentially be used for <br />overburden stockpiles during mining. Setbacks will also be maintained for side slope "cut and <br />fill" reclamation as discussed further in Exhibit E, Reclamation Plan. Additional backfilling <br />following "cut and fill" reclamation will be determined during the mining operation once <br />overburden quantities and general pit depth are determined. In the northern portions of the <br />amendment area, where the pit depth will likely be its greatest, setbacks from the excavation to <br />the permit boundary may be as much as 100 feet. Towards the southern end of the mining <br />operation, however, the pit will become shallower and side slopes will steadily decrease in <br />height, reducing potential setback distances. In addition to "cut and fill" reclamation needs, <br />setbacks from near vertical mining excavations to the permit boundary will generally be twice <br />the adjacent pit depth to mitigate stability risks. <br />The side slopes of the mine pit will be backfilled, graded to a 3H:1 V slope, and seeded as mining <br />progresses. Approximately 3,000 feet of pit side slopes will be created during mining. Since <br />Fountain Pit M -1982 -155 <br />DRMS 112 Permit Amendment <br />Revised in Response to Adequacy Review Comments Page 7 <br />