RPA Overview
The Reclamation Plan Amendment (RPA) area covers 921 acres of the Permanente Quarry site. The plan calls for the site to be reclaimed in multiple phases focused on six areas:
The Quarry Pit
The quarry pit is a 198-acre area on the hillside where mineral extraction has historically occurred. Its elevations range from approximately 550 feet above mean sea level (amsl) to 1,750 amsl, while the surrounding topography ranges from 1,000 ft amsl to 1,750 ft amsl
To reclaim the pit and stabilize the new surface, reclamation of the quarry pit will require backfilling the pit to an elevation of approximately 990 ft amsl and then placing a buttress to stabilize the remaining high walls of the pit, leaving a final slope towards the southeast. Vegetation will be planted to further stabilize the surface.
The pit will be filled with approximately 42 million cubic yards of onsite overburden material, concrete and suitable imported soil.
West Materials Storage Area
The West Materials Storage Area (WMSA) is a 210-acre area where 48 million tons of low-grade limestone and greenstone were previously placed.
The reclamation plan calls for using some of these materials to fill the quarry pit while leaving others in place.
Leaving some materials in place will reduce near- and long-term surface and groundwater quality impacts by avoiding the re-disturbance of previously placed materials.
The WMSA area will be re-graded for stability and capped with cover material and soil for revegetation.
East Materials Storage Area
The East Materials Storage Area (EMSA) is a 65-acre area encompassing 6.5 million tons of low-grade limestone and greenstone overburden material.
The EMSA will be re-graded for stability and capped with cover material and soil for revegetation.
The Shop and Office Area
The Shop and Office, encompassing 64 acres, currently contains crushing stations, offices and maintenance areas. This area will continue to support aggregate operations at the rock plant, and ultimately limited grading is required for geotechnical stability.
Rock Plant Area
The Rock Plant, located on the south side of Permanente Creek, covers 19 acres on gentle slopes.
The Rock Plant is an active processing facility for construction aggregates and will continue operations into the foreseeable future.
Eventually, the equipment and excess materials will be removed, and the area will be re-graded and covered with non-limestone materials.
Permanente Creek Reclamation Area
The Permanente Creek Restoration Area is a 49-acre area located along Permanente Creek.
The slopes along Permanente Creek will be reclaimed. Flattening the slopes will enhance the lower WMSA surfaces, provide improved cover options and long-term stormwater management, and enhance the success of the Permanente Creek Restoration Project.