Lehigh Southwest Cement Co. wants to amend its 2012 Reclamation Plan for Lehigh Permanente Quarry near Cupertino, Calif., to increase mining. As part of the amendment, the proposal asks to disturb an area of the “Permanente Ridge” that is about 100 vertical ft. in height and 4,000 ft. across, according to the Palo Alto Times.
The company’s proposal would effectively “chop the top off” the roughly 20-acre easement, which is protected by a nearly 50-year-old agreement, a move that Santa Clara County supervisors oppose.
The 1972 Ridgeline Protection Easement Deed was made between Lehigh’s predecessor, Kaiser Cement and Gypsum Corp., and the county. It forbids quarrying and mining in the easement area, a roughly 3,000-ft.-long section, and requires Kaiser and its successors to maintain portions of the ridgeline at specific elevations. The deed also allows Santa Clara County to enter the property for inspections “from time to time” regarding preservation of the ridgeline easement.
In its May 2019 proposal to amend its 2012 Reclamation Plan for Lehigh Permanente Quarry, Lehigh said it wants to mine additional limestone from the area and to cut back the slope for stabilization along its north highwall section of the quarry. It also sought to modify the easement agreement to accomplish its goals.
The company wants to expand excavation of the north highwall of the North Quarry Pit; expand surface mining in the new 30-acre Rock Plant Reserve Area south of the North Quarry Pit; reactivate use of the quarry’s existing rock crusher; and haul unprocessed aggregate to the adjacent Stevens Creek Quarry through an internal haul road. The expanded surface mining activities would increase its total production by approximately 600,000 tons.