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Aggregate Resources The Quaternary alluvial deposits of the Hospital Creek alluvial fan are recognized as a source of aggregate for the production of concrete, asphaltic concrete, and road base materials. Aggregate mining has been and continues to be common practice on alluvial fans in southwestern San Joaquin County. The majority of aggregate mined from these alluvial deposits are suitable for the production of Portland Concrete Cement (PCC). The specifications for PCC-grade aggregate are more restrictive than specification for other aggregate products, resulting in an increase in marketability of these deposits. A mineral land classification of aggregate materials in the Stockton-Lodi region conducted by the California Division of Mines and Geology (CDMG) presents an evaluation of the availability of aggregate resources within the area of the project site, as well as other aggregate production regions in San Joaquin and Stanislaus counties (Jensen and Silva, 1988). Evaluation of aggregate resources throughout the State is required by the California Surface Mining and Reclamation Act (SMARA). Provisions of SMARA require that the CDMG determine the boundaries of major aggregate Production-Consumption (P- C) regions, identify aggregate resource areas within the regions, and evaluate the F availability and supply of those resources. Assessment of the aggregate resources includes the classification of Mineral Resource Zones (MRZs) on the basis of existing I geologic data. Identified zones, where sufficient data indicate the likelihood for occurrence of significant aggregate deposits is high, are designated MRZ-2. 1f land uses within MRZ-2 zones are compatible with aggregate mining, the zones are classified as "sectors." Under the State mineral lands classification system, the available tonnage of aggregate resources within sectors is then estimated. The southern half of the project site is located within an identified MRZ-2 zone (Figure 4.2- 3). This area is further designated as a Resource Sector C-7 of the Hospital Creek alluvial fan aggregate production zone. This designation of the area identifies the aggregate resources as "significant mineral deposits" under the State Mining and Geology Board's Guidelines for Classification and Designation of Mineral Lands. The estimated total PCC aggregate resource within Sector C is approximately 194 million tons. The northern portion of the project site is within a MRZ-3 zone. This classification indicates that the area contains aggregate deposits, the significance of which could not be determined during the aggregate classification study: However, subsurface investigations at the project site (Kleinfelder, 1997) confirm that mineable aggregate resources exist in this location. REGULATIONS, PLANS, AND POLICIES SMARA and Related Regulations The California Surface Mining and Reclamation Act (SMARA) was enacted in 1975 to � provide a means of identifying potential mineral resources throughout the State and to Draft Environmental Impact Report 4-12 ER-96-3