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for classification as an area that contains resources that <br /> are either proven or highly likely to contain P. C. C . - <br /> grade aggregate. Relatively clean fine to course grained <br /> sands are present between 10 and 60 feet below ground <br /> surface . The sand in this deposit is composed of fine— to <br /> coarse- grained angular quartz, with varying amounts of <br /> feldspar, heavy minerals, and rock fragments . This material <br /> has been derived from parent rock in the Sierra Nevada to <br /> the east . The size, shape, and stratigraphy of this deposit <br /> suggest it was deposited as a result of the last period of <br /> glacial melting in the Sierra Nevada as opposed to the <br /> current depositional regime of the San Joaquin River. The <br /> material in this deposit extends to depths or approximately <br /> 80 feet below the valley floor. Below the sands is a clay <br /> unit that ranges between 20 and 60 feet in thickness . <br /> Operations will not extend into this clay unit. See <br /> attached geologic and seismic map from the California <br /> Department of Conservation, Division of Mines and Geology, <br /> Special Report 160 . 1 <br /> Seismicity: <br /> The project site is located in a moderately seismic region <br /> along the western margin of California' s Central Valley. No <br /> known active or potentially active faults cross the project <br /> site, and the site is not located in an earthquake fault <br /> hazard zone as established by the Alquist-Priolo Earthquake <br /> Fault Zoning Act . Therefore, ground rupture from faulting <br /> is not considered a significant hazard to structures within <br /> the project site.2 In addition, no new structures or fill <br /> slopes are proposed. There are no dams, tailings, or <br /> chemical processing of the sand. <br /> C. Hydrology: <br /> Ground water is presently found 5 to 15 feet below ground <br /> surface. Sands are present down to an average of 60 feet <br /> below the surface. Below the sands is a clay unit that <br /> ranges between 20 and 60 feet in thickness . Operations will <br /> 1 California Department of Conservation, Division of Mines <br /> and Geology, Special Report 160 <br /> 2 http: //www. consry. ca . gov/CGS/rghm/ap/affected.htm <br /> Special Publication 42 (Fault-Rupture Hazard Zones in <br /> California, by Earl W. Hart and William A. Bryant) <br />