Aggregate Resources in the Los Angeles Metropolitan Area by David J. Beeby, Russell V. Miller, Robert L. Hill and Robert E. Grunwald
The classification of aggregate resources in the three-county area of Los Angeles, Orange, and Ventura, was followed by a "designation" process by the State Mining and Geology Board that formally recognized significant deposits that could provide for future needs. Maps and descriptions of the deposits were placed in the California Public Resources Code and officially transmitted to those county and city governments having decision-making authority over the use of those lands. Those areas are shown on the map in red. To maximize land-use options for local governments, designated areas contain aggregate resources in excess of the region's 50-year need. Since the designation of the aggregate resource areas in the 1980s, about 6 percent of those resources have been covered by urbanization.
A summary of Designation reports and maps released by the SMGB are presented in
Designation is the process by which the SMGB determines that a particular classified mineral deposit is of regional, multi-community, or statewide economic significance. This process is facilitated through analyses by the State Geologist and the California Geological Survey, and information gathered from local communities, the mining industry, and other governmental agencies, such as the Governor’s Office of Planning and Research. The purpose of Designation is to identify those areas that are of prime importance in meeting future needs of the study region and that remain available from a land use perspective.
The objectives of these processes are to provide local agency decision makers with information on the location, need, and importance of mineral resources within their jurisdiction, and to require that this information be considered in local land use planning decisions. These objectives are met through the adoption of local Mineral Resource Management Policies that provide for the conservation and prudent development of these mineral deposits.
One of the first mineral commodities selected by the SMGB for classification by the State Geologist was construction grade aggregates, such as sand, gravel, and crushed rock. The importance of construction aggregate is often overlooked, even though it is an essential commodity in today’s society. Aggregate is a key component in products such as portland cement concrete, asphaltic concrete (macadam), railroad ballast, stucco, road base, and fill materials.
California’s construction industry is greatly dependent on readily available aggregate deposits that are within a reasonable distance to market regions. Aggregate is a low unit-value, high bulk-weight commodity; therefore, aggregate for construction must be obtained from nearby sources in order to minimize costs to the consumer. If nearby aggregate sources do not exist, then transportation costs quickly can exceed the value of the aggregate. Transportation cost is one of the most important factors considered when defining the market area for an aggregate mine operation.
Prior to 1991, the SMGB designated 15 areas within the state, encompassing 259,585 acres, as having regionally significant economic mineral resources. Designation stopped when the costs of complying with requirements of the California Environmental Quality Act became prohibitive, and agency budgets were being reduced because of the “California economic recession” of the early 1990’s. Since that time, no additional areas have received mineral Designation status from the SMGB.
Designation is an effort to conserve mineral resources in regions of expected rapid urbanization or other land uses that might prevent surface mining activities, and therefore result in a loss of the mineral resource to the community. To avoid dictating to local communities where future aggregate mines should be located, mineral designated areas generally contain resources (un-permitted deposits) that are far in excess of the region’s 50-year demand. This attempts to provide maximum flexibility to local governments in making land use decisions, while still conserving an adequate amount of construction aggregate for the future.