GC11B-0996: From Aggregate Availability to Sustainability in California
Authors: Stephen M Testa1, John G Parrish2
Author Institutions: 1. California State Mining and Geology Board, Sacramento, CA, USA; 2. Department of Conservation, California Geological Survey, Sacramento, CA, USA
California leads the nation in the production of sand and gravel, and ranks second behind Texas in the production of portland cement. Prior to 1960, the California Geological Survey (CGS, formerly the Division of Mines and Geology) and the State Mining and Geology Board (SMGB, formerly State Mining Board) placed an emphasis “in obtaining and providing information of benefit to the State’s mineral industry”ù. By the late 1960s, the Division initiated activities in the area of geologic hazards, and also expressed concern over the loss of aggregate resources via urbanization, which were among the state’s most valuable mineral resource. Under the California Surface Mining and Reclamation Act of 1975 (SMARA), the State Geologist classifies mineral resources solely on geologic factors, and without regard to existing land use and land ownership. Following classification, the SMGB may consider “designating”ù such lands should the classified area contain mineral resources of regional or statewide economic significance and that may be needed to meet future demands. In 1979, the classification of aggregate resources in the three-county area of Los Angeles, Orange, and Ventura, was completed, with designation of such resources in Los Angeles County in 1981. Maps and descriptions of the designated mineral lands were placed in the California Public Resources Code and officially transmitted to those county and city governments having permitting authority over the use of those lands. In 1999, the SMGB in concert with CGS implemented the SMARA Regional Synthesis Map series, with the first (and last) of the series covering the Los Angeles Basin. This map was very useful for regional planners and the general citizenry since it provided a broader perspective not readily apparent in the smaller scale Production-Consumption (P-C) regional maps. CGS’s statewide Aggregate Availability Map, commonly referred to as Map Sheet 52, was developed in 2002 and updated in 2006. The purpose of Map 52 was to compare projected aggregate demand for the next 50 years with currently permitted aggregate resources in 31 “production-consumption”ù regions of the state, and flag regions where there were less than 10 years of permitted aggregate supply remaining. The 31 P-C aggregate study areas covered about 25 percent of the State’s geography, but about 90 percent of California’s population. It was shown that in the next 50 years, California was projected to need approximately 13.5 billion tons of aggregate, excluding needs associated with accelerated construction programs or from reconstruction following a major, damaging earthquake. Map 52 demonstrated the need for more permitting of mineral resources, but did not address the overall effectiveness of the state’s efforts to protect aggregate resources, or aggregate sustainability. To address the effectiveness of the state’s overall efforts to conserve and address aggregate sustainability, new maps are being considered. Such maps may incorporate other factors to reflect the pace of urbanization, quality of the mineral resource, and environmental factors (i.e., sensitive habitat, wildlife refuge, etc.), material haul distances, infrastructure (suitability of roads and bridges) condition, and greenhouse gas emissions.