Permanente Quarry

Permanente Quarry is a limestone mining site located on the northeast slopes of Black Mountain in Santa Clara County. The deposits were formed from ancient seamounts approximately 100 million years ago and span thousands of acres.

Mining began as a small operation in 1902 before Henry Kaiser purchased the site in 1939 to supply cement for Shasta Dam construction. This acquisition transformed it into a major production facility for regional building projects.

This quarry supplied materials for major infrastructure projects across Northern California, including highways, dams, and airports throughout the 20th century. The limestone extracted here shaped the built environment that people still use and see today.

The site remains an industrial area with active operations, so visitors should expect working conditions and limited public access. Plans are underway to transform portions into open space and housing, which may affect the accessibility of certain areas.

During World War II, this facility employed roughly 2000 workers and supplied all cement used by the Navy throughout Pacific Theater operations. This role made it one of the most important industrial sites supporting the war effort on the West Coast.