Officials in Santa Clara County and Cupertino on Tuesday signed off on an agreement on how to jointly manage possible future development proposals for the Permanente Quarry site.

The limestone quarry and cement kiln owned by Lehigh Southwest Cement Company is expected to cease operations at an unspecified future date.

The 3,510-acre property is mostly on unincorporated county land, with portions also inside the city limits of Cupertino and Palo Alto, according to county officials.

“With Lehigh stating its willingness to close the cement plant, there's no better time for our two jurisdictions to work together to come up with a mutually agreed upon policy framework for how we consider future uses on the site,” said Simitian.

The agreement is intended to ensure that restoration and redevelopment of the site is done in a way that protects public health and the environment, Simitian said in a news release.

It was unanimously approved on June 21 by the Cupertino City Council and on June 27 by the County Board of Supervisors.

“Our city and residents have lived with the impacts of an industrial neighbor for many decades, and we're feeling hopeful about a cleaner, quieter future that is safe, healthy, and more compatible with our community,” said Cupertino Mayor Hung Wei.

A second agreement between the county and Heidelberg Materials, the company that owns the Lehigh site, would ensure the cement plant's permanent closure and is expected to come before the Board of Supervisors at its meeting on Aug. 15, according to the news release.