Clayton Quarry Reclamation Plan Amendment

3 Documents in Project


SCH Number
Lead Agency
Contra Costa County
Document Title
Clayton Quarry Reclamation Plan Amendment
Document Type
EIR - Draft EIR
Document Description
The applicant, CEMEX Construction Materials Pacific, LLC (CEMEX) (2365 Iron Point Road, Suite 120 Folsom, CA 95630, (916) 521-0222), is requesting approval of a revised Reclamation Plan (County File #’s CDLP15-02030 and 31), which includes the following components: • Reclamation over an anticipated period of 47 years to a post-mining land use of open space; • Reduction of the surface mining disturbance footprint relative to the approved reclamation plan that leaves the east rim of the quarry intact, providing a visual buffer between the quarry and view sheds to the east; • Permanent overburden fill areas; • Final grading contours reflecting a maximum depth of excavation at elevation 110 feet above mean sea level (msl) with finish slope angles that achieve adequate factors of safety; • A final drainage plan that provides for the quarry pit to slowly fill with stormwater following reclamation to form a quarry lake with a controlled outflow that conveys stormwater to natural drainage courses and man-made drainage facilities; • Removal of facilities, structures and equipment associated with mining; • Revegetation of the quarry east rim, overburden fill areas, and processing plant site to a combination of chaparral and grassland habitats that feature California native seed mixes; • Elimination of requirements to backfill, grade, and compact the quarry floor and benches, given that the planned open space end use would provide for a future quarry lake; • Clarification of pre-Surface Mining and Reclamation Act (SMARA) (1976) disturbance areas, including any areas disturbed outside the boundaries of the approved reclamation plan; • A tree permit request to remove 79 out of 123 existing trees, to be replaced with 400 foothill pine trees that would form a tree screen along the quarry east rim; • Compliance with current State reclamation standards to be achieved during reclamation; • An exception request to Division 914 of the Contra Costa Code of Ordinances (Offsite Collect and Convey requirement). In addition, and in response to stakeholder input, CEMEX has incorporated into the project a new screening berm (between the existing processing plant site and residential communities to the north).

Contact Information

Francisco Avila
Agency Name
Contra Costa County Department of Conservation and Development
Job Title
Principal Planner
Contact Types
Lead/Public Agency

Bruce Steubing
Agency Name
Benchmark Resources
Job Title
Project Manager
Contact Types
Consulting Firm

Steve Grace
Agency Name
CEMEX Construction Materials Pacific, LLC
Job Title
Contact Types
Project Applicant


Contra Costa
Countywide, San Francisco Bay Area
Cross Streets
Mitchell Canyon Road and Diablo Downs Road
Total Acres
Parcel #
112-020-007 and 112-010-016
Pine Hollow, Mt. Diablo, and Highlands
Mitchell Creek
14, 23

Notice of Completion

State Review Period Start
State Review Period End
State Reviewing Agencies
California Air Resources Board (ARB), California Department of Conservation (DOC), California Department of Fish and Wildlife, Bay Delta Region 3 (CDFW), California Department of Resources Recycling and Recovery, California Department of Transportation, District 4 (DOT), California Department of Water Resources (DWR), California Governor's Office of Emergency Services (OES), California Native American Heritage Commission (NAHC), California Natural Resources Agency, California Regional Water Quality Control Board, San Francisco Bay Region 2 (RWQCB), California State Lands Commission (SLC), Department of Toxic Substances Control, Office of Historic Preservation, State Water Resources Control Board, Division of Drinking Water, State Water Resources Control Board, Division of Water Quality, California Department of Parks and Recreation
State Reviewing Agency Comments
California Department of Parks and Recreation
Development Types
Mining (Mineral Aggregate)
Local Actions
Use Permit, Reclamation Plan Amendment
Project Issues
Aesthetics, Agriculture and Forestry Resources, Air Quality, Biological Resources, Cultural Resources, Cumulative Effects, Drainage/Absorption, Energy, Flood Plain/Flooding, Geology/Soils, Greenhouse Gas Emissions, Growth Inducement, Hazards & Hazardous Materials, Hydrology/Water Quality, Land Use/Planning, Mineral Resources, Noise, Population/Housing, Public Services, Recreation, Transportation, Tribal Cultural Resources, Utilities/Service Systems, Vegetation, Wetland/Riparian, Wildfire
Local Review Period Start
Local Review Period End


Notice of Completion [NOC] Transmittal form
State Comment Letters [Comments from state reviewing agencies]

Disclaimer: The Governor’s Office of Planning and Research (OPR) accepts no responsibility for the content or accessibility of these documents. To obtain an attachment in a different format, please contact the lead agency at the contact information listed above. You may also contact the OPR via email at or via phone at (916) 445-0613. For more information, please visit OPR’s Accessibility Site.

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