4.10 MINERAL RESOURCES

Transcription

1 4.10 MINERAL RESOURCES SCOPE AND METHODOLOGY This section examines the City s predominant mineral resource, aggregate, and the current mining operations in place to extract aggregate. Reclamation and reuse of the mines is also discussed. The primary source for this section was the City of Azusa Analysis of Existing Conditions and Trends report. ENVIRONMENTAL SETTING The City lies upon the alluvial fan of the San Gabriel River, a widespread bed of sand, gravel, cobbles, and boulders deposited by the river as it emerges from the south slopes of the San Gabriel Mountains. Due to permeability of this material, surface and groundwater moves readily through these deposits, feeding the potable water aquifers and producing standing water where excavations have gone below the local groundwater table. Gold was discovered in the alluvial deposits in 1857, and was mined in the area for several decades. More recently, these alluvial fan deposits have proven a rich source of aggregate. Aggregate is a mineral necessary for the production of concrete, road base, and related building materials, and significant demand for aggregate is the generated by rapidly developing Los Angeles metropolitan area. Only aggregate is mined at present, although millions of dollars worth of gold was historically extracted from the Azusa area. The City of Azusa lies within the San Gabriel Fan District, which is a designated aggregate production zone. Aggregate from this district is of very high quality, and is used to set engineering standards for concrete in the region. Five aggregate sectors (A through E) have been identified within the San Gabriel Fan District. The sectors of concern for the City of Azusa are Sectors A, B, and E and have an estimated aggregate resource of 280 million tons in Sector A, 200 million tons in Sector B, and 360 million tons in Sector E. 1 Annual aggregate production in the San Gabriel Fan District has ranged from about 13.5 to 20.0 million tons since the early 1980s, with an average annual production of approximately 16.5 million tons 2. The total aggregate reserve in the San Gabriel Fan District is estimated to be able to sustain current extraction rates for the next 50 years. Aggregate resources are considered critically important resources. The aggregate resources in Azusa are considered to be significant because of their location in a region that has a high demand for aggregate, and availability is becoming restricted. Since the cost of aggregate is largely affected by the cost of transportation, the availability of aggregate close to developing areas is critical. Protection of the resources, and their continued availability, is a State policy. 1 Division of Mines and Geology Open File Report 94-14, Update of Mineral Land Classification of Portland Cement Concrete Aggregate in Ventura, Los Angeles, and Orange Counties, California, Part II Los Angeles County. 2 Miller, Russell V., Changes in Construction Aggregate Availability in Major Urban Areas of California Between the Early 1980s and the Early 1990s. California Geology, January/February 1997: pp

2 Existing Mining Operations Three quarry mining operations are active in the City of Azusa, two operated by Vulcan Materials (Azusa Rock and Reliance Azusa Mines) at the northwestern edge of the City, and the other operated as a mine and landfill by Cemex and Waste Management International (WMI), respectively, on the valley floor adjacent to the City of Irwindale. A map of these three mines is provided as Figure A fourth operator, San Gabriel Rock, removes sand and gravel from the riverbed as an ongoing maintenance operation under contract with the U.S. Army Corps of Engineers. The mining areas in Azusa are classified as a MRZ - 2 by the California Department of Conservation. A MRZ - 2 is defined as an area where adequate information indicates that significant mineral deposits are present, or where it is judged that a high likelihood exists for their presence. This is a state classification to be recognized in local land use planning. The Vulcan operations lie north of the San Gabriel River and include extraction and crushing of rock at the base of the mountain. The Vulcan Material - Azusa Rock Mine is exposed and is visible from a considerable distance within the San Gabriel Valley and Los Angeles Basin. Azusa Rock Mine operations use heavy-duty equipment and blasting to remove rock from the hillside. The rock material is transported via conveyor belt approximately 2 miles to the Reliance Azusa Plant, located in the City of Irwindale. The Vulcan Material - Reliance Azusa Mine (MRZ - 2) is an open pit facility located on relatively flat terrain and, for this reason, it is not as visible. Rock materials from this mine are also transported via a conveyor belt to the Reliance Azusa Plant, on the mine site and due west of the current pit area. The WMI mine (MRZ - 2) operations lie at the southwestern edge of the City of Azusa, bordering the cities of Irwindale and unincorporated Los Angeles County areas. This site comprises an older mine, now being operated in four distinct operations, including aggregate mining, a concrete batch plant, an inert landfill, and a site for a proposed municipal waste transfer station. Land Use Conflicts and Reclamation. As growth and development has occurred in California, the demand for aggregate resources has increased at the same time as the locations rich in aggregate resources have been developed with uses that are often incompatible with mining activities. The locations where aggregate resources are found in Azusa include areas with scenic qualities, areas with high open space value, and areas with desirable residential potential. Land use conflicts to be addressed include not only the conflicts between operating mines and adjacent land uses, but also conflicts between the need for aggregate and the need for the other resources that the land in which aggregate is found represents. Balancing the positive aspects of mining, including employment and its contribution to the industrial base of the town, and mining s potential to limit Azusa s ability to attract the types of new development it wishes to attract, is a challenge. The proposed General Plan Policies would help to mediate the potential conflict between mining and other development interests. In providing for the continued operation of the mines described above, the Mineral Resource policies acknowledge the importance of MRZ 2 areas and the need to extract significant mineral resources. Alternately, the proposed General Plan policies emphasize efficient reclamation of mines as quarries become phased out and can be adopted for other land uses. The Reliance site doesn t specifically state a reclamation use, but discusses agriculture, industrial, recreation, and landfill. The Vulcan site does not have a reclamation plan as it predates regulations in the California Surface Mining and Reclamation Act

3 Figure Mine locations

4 SIGNIFICANCE CRITERIA This assessment presented below uses the following criteria as a guide to identifying potentially significant adverse mineral resource issues resulting from the proposed project. Specifically, a significant impact would result if the proposed project: Results in the loss of availability of a known mineral resource that would be of value to the region and the residents of the state; or Results in the loss of availability of a locally important mineral resource recovery site delineated on a local general plan, specific plan or other land use plan. ENVIRONMENTAL IMPACTS The policies of the proposed General Plan would maintain the mining operations that are an important part of Azusa s economic base. The Department of Conservation has classified the aggregate deposits in Azusa and in the surrounding jurisdictions as mineral resources of regional importance. The classified area is larger than those areas currently mined. The proposed General Plan s Mineral Resources policies recognize the presence of the aggregate resources and the State s designation in that the City will continue to permit existing mining at its present location for the next ten to thirty-five years. Expanded mining operations will be subject to local approval. Access to additional mineral resources could possibly be lessened; however, the amount of aggregate mineral resources potentially rendered unavailable for mining could represent a very small fraction of the total aggregate mineral reserves available in the region. The policies and associa ted programs focus on reducing the adverse visible and ecological effects that mining can have on the land and natural environment. The policies and programs listed below promote the reduction of visible impacts from mining through the timely reclamation of mines as each phase of mining is completed, the re-vegetation of mining areas prior to complete reuse, rock staining to minimize the contrast between mined and un-mined areas, and the use of screening, where feasible, to block views of mining activity or equipment. Policies stating that re-vegetation shall occur with native plants would aid in covering mining scars, stabilizing slopes, and recreating the naturally occurring environment. Program MR3 ensures that the mine operations are part of the planning process and that the City has the opportunity to periodically review the operations. Involvement of the mine operator in all phases of the reclamation process, as stipulated in programs MR6 and MR8, would facilitate efficient reuse of the mines. These policies are as follows: 1.2 While permitting mineral resource extraction and processing, encourage relocating mining operations to less environmentally sensitive and less visible locations and to areas of more compatible land uses. 1.4 Limit effects of mining operations on residents, businesses, and visitors to Azusa. Effects include but are not limited to visual impacts, noise, dust, and truck traffic. 1.5 Limit effects of mining operations on biological and recreational resources. Effects include but are not limited to effects on adjacent vegetation of runoff, erosion, and dust, effects due to vegetation removal, effects on wildlife and recreationalists of noise and vibration. 1.6 Minimize additional visual changes to the hillsides visible from Azusa. The associated programs include: MR1 Work with other jurisdictions in the region to encourage aggregate recycling, for example,

5 Support other jurisdictions approval of projects involving aggregate recycling; and Participate in regional programs supporting aggregate recycling. MR2 Provide incentives for the timely redevelopment of mine sites and revegetation with native plants to General Plan designated post reclamation uses. Incentives can include: Target high value land use, including land use type, density bonus, etc.; Redevelopment incentives; Early permitting for proposed post-reclamation land uses, when proposed prior to the completion of mining; and Increased density or other variations in development requirements where appropriate. MR3 The mining ordinance shall: Continue to: o Require a Conditional Use Permit for mining activities. o Require a Conditional Use Permit and Reclamation Plan Amendment for permit amendments to increase area or volume mined and changes timing of mining and reclamation. Require compliance review of Conditional Use Permits and Reclamation Plans every five years, and require renewal every ten years. MR4 MR5 MR6 MR7 Require Reclamation Plans to propose a post-reclamation use consistent with the General Plan designation for the site, and to establish compatible post-mining conditions. Mine plans shall be designed such that phases of mining can be reclaimed at the completion of each phase. Each phase of mining shall be initiated and completed within one year. Work with mine operators to reclaim areas where mining is completed as soon as possible, rather than waiting for completion of all phases of mining. Provide incentives such as approval of requested amendments to permits or streamlined permit processing. Mines and reclamation plans shall include measures to minimize the mining and reclamation impacts. Measures shall include, but are not limited to: mining in areas not visible to inhabited areas; rock staining to minimize the contrast between mined and unmined areas; reclamation of mined areas and revegetation with native plants within one year or less of the initiation of a phase of mining; temporary covering or revegetation with native plants in idle mining areas prior to reclamation; installing and maintaining a screening, where feasible, to block views of mining activity and/or equipment; and state of the art dust control measures. MR8 Amend the Development Code and other ordinances regulating mining to require: computer generated photo-realistic visual simulations to be submitted with any mining and/or reclamation plan or proposed change to a mining and/or reclamation plan. The visual simulations are required to show views of the mine site from up to three locations in Azusa selected by the

6 Planning Division under several scenarios (1) existing, (2) at the cessation of mining, (3) post reclamation, and (4) at key interim points during mining and reclamation; mining and reclamation resulting in natural appearing contours and to require actions to minimize visual effects of mining activities (e.g. rock staining to minimize scars on slopes in visible locations); and that consideration of the appearance of mined areas both during mining and reclamation and postreclamation be addressed in mining and reclamation plans. As the proposed General Plan policies would not result in the loss of availability of aggregate while ameliorating some of the adverse consequences of mining, no significant impact to mineral resources is anticipated. MITIGATION MEASURES No significant impacts to mineral resources are anticipated; therefore, no mitigation measures are recommended. LEVEL OF IMPACT AFTER MITIGATION No significant impacts to mineral resources are anticipated