CEMEX Clayton Quarry Reclamation Plan Amendment

CEMEX Clayton Quarry Reclamation Plan Amendment

The applicant is requesting approval of two land use permits (County File #’s LP15-2030 and 2031) for the purposes of amending it reclamation plan and corresponding operations, which includes the following components: • Reclamation over an anticipated period of 50 years to a post-mining land use of open space; • Reduction of the surface mining disturbance footprint that leaves the east rim of the quarry intact, providing a visual buffer between the quarry and viewsheds to the east; • Permanent overburden fill areas; • Final grading contours reflecting a maximum depth of excavation at elevation 110 feet mean sea level 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 human-made drainage facilities; • 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 will provide for a future quarry lake; • Clarification of pre-1976 (pre–California Surface Mining and Reclamation Act (SMARA)) disturbance areas, including any areas disturbed outside the boundaries of the 1983 Reclamation Plan; and • Achievement of current State reclamation standards during reclamation. In addition, and in response to stakeholder input, CEMEX has incorporated into the Revised Reclamation Plan a new screening berm (between the existing processing plant site and residential communities to the north) and an alternate driveway for accessing the site farther north along Mitchell Canyon Road.

Clayton

Contra Costa

Unincorporated

California Air Resources Board (ARB), California Department of Fish and Wildlife, Bay Delta Region 3 (CDFW), California Department of Parks and Recreation, California Department of Resources Recycling and Recovery, California Department of Toxic Substances Control (DTSC), California Department of Water Resources (DWR), California Governor's Office of Emergency Services (OES), California Natural Resources Agency, California Regional Water Quality Control Board, San Francisco Bay Region 2 (RWQCB), California State Lands Commission (SLC), Office of Historic Preservation, State Water Resources Control Board, Division of Water Quality, California Native American Heritage Commission (NAHC), California Department of Conservation (DOC), California Department of Transportation, District 4 (DOT)

California Native American Heritage Commission (NAHC), California Department of Conservation (DOC), California Department of Transportation, District 4 (DOT)

Mining (Amendment to reclamation plan of existing quarry operation.)(Mineral Diabase)

Use Permit

Aesthetics, Air Quality, Biological Resources, Drainage/Absorption, Geology/Soils, Greenhouse Gas Emissions, Hydrology/Water Quality, Land Use/Planning, Mineral Resources, Noise, Tribal Cultural Resources, Vegetation