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Lehigh Information

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Lehigh Quarry & Cement Plant Info 


The Lehigh Hanson Cement Plant is located off of Stevens Creek Boulevard in

the western hillsides of Santa Clara County, west of the City of Cupertino. Because the facility is not located in the City of Cupertino, therefore, the City cannot currently impose any operational conditions on the quarry or the cement plant. The City does maintain an active interest on operations particularly as they may impact health and safety within the City.


Lehigh Public Informational Meeting - February 13, 2020


November 2018 Lehigh updates

Report to Council regarding Lehigh noise January 24, 2017
Letter from Mayor to Supervisor Simitian regarding Lehigh Noise January 24, 2017
Santa Clara County - Permanente Quarry (Lehigh/Hanson) site

As a courtesy to its residents, the City of Cupertino maintains this collection of official notices and correspondences, received by the City. Every attempt is made to keep information on the website updated and current. If you are searching for a specific document and do not see it, please let us know by contacting our webmaster at Source agencies should be contacted for authoritative documentation on topics within their respective jurisdictions.

Lehigh Cement Plant Noise Monitoring Report - November 29 2016

Lehigh Permanente Compliance Annual Report #3

Notice of Public Hearing - County of Santa Clara, November 4, 2015 at 7 pm
Watch the Meeting Video 

Los Altos Hills, Re: Consent Decree United States v. Lehigh Cement Co. - May 29, 2015

City of Los Altos, Re: Consent Decree United States v. Lehigh Cement Co. - May 28, 2015

City of Cupertino, Re: Consent Decree United States v. Lehigh Southwest Cement Co. - May 20, 2015

San Francisco Bay Regional Water Quality Control Board letter about Feasibility of Treating Runoff from the East Material Storage Area at Lehigh - April 15, 2015

Lehigh letter to Bennett, March 23, 2015 - re Proposition 65 Notice concerning Lehigh Southwest Cement Company

Notice of Violation - Clayton & McEvoy - January 30, 2015

Notice of Public Hearing - County of Santa Clara, Department of Planning & Development , November 20, 2014 at 1:30 pm

Notice of Public Hearing - Santa Clara County Planning Commission, November 21, 2013 at 1:30 pm

California Water Boards Letter for the Cupertino City Council Meeting on September 5, 2013

Legal Memorandum from Cupertino City Attorney - Lehigh Quarry and-Cement Plant - August 12, 2013

San Francisco Bay Regional Water Board investigative Order No. R2-2013-0005 issued to Lehigh Southwest Cement Company on January 22, 2013, has been amended. Download the Amended Order R2-2013-0005-A1 Order with a transmittal letter, a fact sheet about Water Code section 13267 orders, and interested party mailing list for matters associated with Lehigh Southwest Cement Company - June 27, 2013

San Francisco Bay Region Water Quality Control Board - Notice of Violation of California Water Code Section 13260, for Lehigh Southwest Cement Company - January 22, 2013

San Francisco Bay Region Water Quality Control Board - Staff Comments on the Workplan for Characterization of the Eastern and Western Materials Storage Areas - January 22, 2013

Cupertino: Air district approves new regulatory rules for Lehigh Cement - San Jose Mercury News

Notice of Public Hearing, Tuesday, June 26, 2012, to consider an appeal of the decision by the Santa Clara County Planning Commission, made on June 7, 2012, granting approval of the Permanente Quarry Reclamation Plan Amendment and certification of the Environmental Impact Report

Bay Area Air Quality Management District Board of Directors Meeting & Lehigh Tour, May 21, 2012, 10 am Cupertino Room at Quinlan Community Center, 10185 N. Stelling Road, Cupertino
Watch the Meeting Video 

Lehigh Title V Permit Renewal Notice

Bay Area Air Quality Management District- Public Workshop to present, discuss, and receive comments on the draft Regulation 2 (Permits), Rule 1 (General Requirements), Rule 2 (New Source Review), Rule 4 (Emissions Banking), and Rule 6 (Major Facility Review) - Wednesday, February 22, 2012, 9:30 am

Notice of Public Meeting - Lehigh Southwest Cement Company,  Public Oral Comments on the Draft Environmental Impact Report, February 2, 2012, 1:30 pm

IRIS Environmental - Lehigh-Technical-Memorandum - January 19, 2012

Santa Clara County planners received input from residents regarding the Lehigh Permanente Quarry draft environmental impact report (EIR). A section of the EIR considers a reclamation plan amendment for 1,238 acres of adjacent land, including the 75-acre East Materials Storage Area. The event was scheduled on January 26, 2012 at the Quinlan Community Center, Cupertino.
Watch the Meeting Video 

County of Santa Clara - Notice of Availability - The Lehigh Quarry Reclamation Plan Amendment Draft Environmental Impact Report - December 23, 2011

Bay Area Air Quality Management District posted a Draft Regulation, Workshop Notice and Report for Proposed Regulation 9, Rule 13 which will affect Portland Cement Manufacturing facilities. You can find these documents at their website.

Workshop Information
Monday, December 12, 2011, Monta Vista High School Cafeteria, 21840 McClellan Road, Cupertino, CA
Watch the Workshop Video 

Notice of Public Hearing for Lehigh Property, Tuesday, Aug 23, 2011 

Notice of Intent to Sue for Violations of the Clean Water Act at Lehigh 

Office of Mine Reclamation,  Reclamation Plan Non-Compliance 

Lehigh Southwest Cement – Permanente Facility – Additional Information to Support Lehigh’s Request for Revised Submission Schedule for June 14, 2011 Section 13267 Order

Lehigh Southwest Cement – Permanente Facility - Request for Revised Submission Schedule for June 14, 2011 Section 13267 Order

California Regional Water Quality Board - Request for revised submission schedule for June 14, 2011, Section 13267 Order

California Regional Water Quality Control Board - Notice of Violation for unauthorized discharge to Permanente Creek - June 14, 2011

Lehigh Southwest Cement Company – Administrative Civil Liability Complaint No. R2-2011 – Submittal of Waiver Form

Extending Public Comment Period for of an Environmental Impact Report for the Lehigh/Permanente Quarry Comprehensive Reclamation Plan Amendment and Use Permit - Comment Period will close on May 23, 2011,  5:00 pm.

Bi-Annual Santa Clara County Surface Mine & Reclamation Act (SMARA) Program Update Report - March 17, 2011

State Mining and Geology Board Executive Officer's Annual Report For 2011-2012

Public Hearing Notice

Public Scoping Meeting - March 30, 2011

County of Santa Clara Board of Supervisor's Public Hearing Notice - Tuesday, February 8, 2011 at 1:30 pm

Cupertino Chamber of Commerce: Lehigh Support Letter

Santa Clara Updates

Bi-Annual SCC SMARA Update, September 6, 2011   

County Letter re Recent Reports Related to Permanente Quarry, October 15, 2010

County Response to City Manager Letter December 7, 2010

City of Cupertino
Cupertino Letter to Bay Area Air Quality Management District- February 7, 2012

City Council December 21 Meeting - State Mining & Geology Board Info

Public Hearing Notice
Santa Clara County Date Uncertain Notice

November 23 Hearing - Date Changed to Date Uncertain

Tuesday, November 23, 2010 at 1:30 pm

Letter from Cupertino Mayor & City Manager - November 10, 2010

Violation Notices

Lehigh Letter to Regional Water Board re NOV (2-25-11)

Notice of Violations and Requirement to Obtain Coverage for Discharges to Waters of the U.S. under Different Permit - February 18, 2011

SF Bay Regional Water Quality Control Board - Notice of Violation - March 26, 2010

EPA 2010 Clean Air Act Violation - March 10, 2010

Santa Clara County Notice of Violation - June 20, 2008

Santa Clara County Notice of Violation - October 10, 2006

Compliance Schedule Modification of the October 10, 2006 Notice of Violation

Santa Clara County Board of Supervisors Response to Public Comments 

Information from Lehigh Permanente
World Journal Article Lehigh 10-31-2010

Lehigh Response: Requirement for Technical Report to Document Non-Storm Water Discharge(s) Pursuant to California Water Code Section 13267

Lehigh Permanente - December Information Update

Lehigh Permanente 10/19 Information Update

Response City Council Study Session

Santa Clara Valley District Response

City Council Study Session - July 20, 2010
Bay Area Air Quality Management District Presentation

County of Santa Clara Update

Related Info

Bay Area Air Quality Management District’s Proposed CEQA Guideline

Adopted Air Quality CEQA Thresholds

Lehigh Meeting Related Videos

BAAQMD Workshops

Notice of Preparation of an Environmental Impact Report For Reclamation Plan Amendment For Permanente Quarry
Info for Public Scoping Meeting
April 28, 2010 at 6:30 pm at Cupertino Community Hall

Neighborhood Meeting
The City of Cupertino conducted a neighborhood meeting with the Bay Area Air Quality Management District (BAAQMD) to position an ambient air monitoring station in Cupertino to measure our air quality on April 29, 2010. Monta Vista Park was identified as a suitable location that will provide a representative.   The City of Cupertino facilitated this neighborhood meeting in order for BAAQMD to present information on the technical specifications of the station and facilitate an open forum for resident questions.

Details of the Meeting.

BAAQMD Presentation

Mayor's Response - May 4, 2010


Response to the Study Session
<-- Lehigh Quarry and Cement Plant Memo from City Attorney - January 1, 2011-->

Regional Water Quality Control Board - Letter to City Manager about Stevens Creek Reservoir and Mercury, dated January 21, 2010

Environmental Protection Agency - Response to Letter, Dated January 21, 2010

Bay Area Air Quality Management District - Response to Letter, Dated January 21, 2010

Study Session to Learn about Regulation of the Lehigh Cement Plant - January 12, 2010
The following speakers gave the presentation:

  • US Environmental Protection Agency
    Shaheera Kelly, EPA Region 9, Lehigh Title V Permits Ofc Lead
    EPA Presentation
  •  Bay Area Air Quality Control District
    Jack Broadbent, Chief Executive Officer
    Brian Bateman, Director of Engineering
    BAAQMD Presentation
  • Regional Water Quality Control Board
    Representative of Bruce Wolfe, Executive Director
    Regional Water Quality Control Board Presentation
  • County of Santa Clara
    Jody Hall Esser, Director, Department of Planning and Development
    Gary Rudholm, Senior Planner
    SCC Presentation

General Overview
The quarry is a limestone and aggregate mining operation containing over 900 acres and includes the main mining pit, the west material storage area, and the east material storage area. According to state records, mining began in the early 1900s and is done pursuant to a legal nonconforming use. The existing and on-going activities are drilling, blasting, extraction of blasted rock, processing to size and sort the raw materials, stockpiling of construction aggregate and excess materials, reclamation activities, and the transportation of processed materials from the site. Mining is anticipated to continue for another 20-25 years.

The cement plant is located adjacent to the mine and produces Portland cement – a fine gray powder that binds sand and aggregate into concrete. Portland cement is the generic term for the type of hydraulic cement that is used in virtually all concrete. Raw materials used in Portland cement manufacturing are comprised of calcium, silica, alumina, and iron. Although cement can be formed from a wide variety of materials, one of the most common combinations of raw materials is limestone, clay and sand. At the Lehigh facility, materials containing these minerals are mined in a quarry, ground to a fine powder, and blended in specific proportions needed for the final cement product. The finely ground mixture of raw materials are heated until partially molten in a cement kiln to produce a pellet-shaped, glass-hard material called clinker. The clinker is then ground with gypsum to an extremely fine powder, Portland cement.

Primary emissions in the manufacturing of Portland cement at the Lehigh facility are combustion emissions, point-type particulate, and fugitive particulate. Plant operation is monitored and controlled by computer. The real-time computer system monitors feed rates and other parameters to optimize combustion control. Combustion emissions are generated in the pyroprocessing operation. Particulate emissions are generated throughout the facility from numerous stationary and mobile-type operations.

Use Permit
The Lehigh Cement operation is authorized under a use permit from the County of Santa Clara. A use permit for the cement plant was first issued on May 8, 1939. The use permit was modified in June 1950 and May 1955 to add rotary kilns to the operations. The County approved a use permit modification associated with modernization of the cement plant on December 5, 1977.

The Lehigh facility has some operational aspects that are continuous, namely the kiln operation since the kiln has to be at extremely high temperatures and cannot be realistically turned off and then back on every day.

The County use permit does not contain any conditions related to hours of operation or to the number of trucks or truck traffic routes. The only condition with regard to noise is that noise at the property line must conform to the County noise element and County ordinances.

The County currently does not have a continuous noise monitoring program in place. Lehigh is required to comply with the Santa Clara County noise ordinance and enforcement of those standards is by the County Department of Environmental Health (408.918.3400). The County Planning Office contracted with an outside consultant to conduct noise monitoring during the summer of 2009, to provide information regarding current noise levels, and to help determine whether noise levels are within County requirements. The County also has contracted with a consultant to evaluate truck traffic.

The public may contact the County Planning Office (408.299.5770) if there are complaints regarding the cement plant and its operations. The Planning Office staff will investigate the complaint, determine whether a violation of County zoning regulations or other ordinances have taken place, and begin enforcement of the regulations where violations occur. The nature of enforcement varies, as with every violation found by County inspectors, depending on the type of violation. To be included on a County mailing list of future notifications for this project, please send an email to

Reclamation Plan
In 1975 the State of California adopted the Surface Mine and Reclamation Act, which mandates that all active surface mines have reclamation plans approved by the local jurisdiction. The County of Santa Clara approved the reclamation plan for what was then called the Permanente Quarry on March 7, 1985. This plan is valid for a period of 25 years, and will expire in March 2010.

Lehigh’s predecessor submitted an application for a reclamation plan amendment in January 2007. An amendment to a Reclamation Plan is a change to an existing, approved plan. The proposed amendment to the Quarry reclamation plan, on file with the County of Santa Clara, would reconfigure the mining and materials storage areas through grading activities that would include cutting benches in the bedrock, backfilling excavations with mining overburden material, and re-vegetation of the final slopes created by this process. An area on the west side of the pit from which minerals are extracted is a stockpile area that receives overburden from the pit. This stockpile is required under the existing reclamation plan to be re-vegetated and to provide for proper drainage and erosion control. The proposed amendment would include disturbed areas that are currently outside the reclamation plan boundary, but which are used regularly as part of mining activities. An area on the east side of the pit would be designed by the proposed amendment to receive overburden materials as well. The resulting slopes would be re-vegetated and engineered to provide for proper drainage and erosion control. The proposed expansion would also include a new, second mining pit on the property.

The County of Santa Clara is the lead agency responsible for approving reclamation plans and amendments for surface mines within the unincorporated areas of the County. This authority stems from the County zoning regulations adopted by the Board of Supervisors, and from the State Surface Mining and Reclamation Act. Under County zoning regulations, following completion of environmental review as required by the California Environmental Quality Act (CEQA), the County Planning Commission approves new reclamation plans and amendments to existing plans. A decision by the Planning Commission may be appealed to the Board of Supervisors.

After an initial review of the project plans the County began the environmental impact review process consistent with requirements under CEQA, which included two scoping meetings with Cupertino residents. The top environmental issues associated with the proposed reclamation plan amendment include geology and slope stability, visibility of the new pit, visibility of the placement of over-burden materials, biology, hydrology and drainage, and air quality.

During the required CEQA review, the County found that detailed geologic analysis is required regarding slope stability. Because this analysis may lead to modifications of the plans included in the amendment, work on the Draft Environmental Impact Report (DEIR) ceased until the geologic analysis is complete. Once the CEQA review is complete the County will circulate a DEIR for review by responsible agencies and the general public. For further information on the County Reclamation Plan, please contact Mark Connolly at the Santa Clara County Planning Department:

Air Quality 
Baghouses are installed to recover product and control dust emissions from the kiln, mills, clinker cooler, fuel mill, belt conveyor transfer points, bulk unloading stations and at numerous other locations at the facility. Water is sprayed on haul roads and uncovered storage piles to control fugitive dust generation. Facility maintenance activities and practices such as watering of road surfaces and enforcement of the speed limits reduce the quantity of fugitives generated on-site and limit their transport off-site.

This facility is subject to the Operating Permit requirements of Title V of the federal Clean Air Act, Part 70 of Title 40 of the Code of Federal Regulations, and  BAAQMD Regulation 2, Rule 6, Major Facility Review. It is a major facility because it has the “potential to emit” more than 100 tons per year of a regulated air pollutant. This facility received its initial Title V permit on November 5, 2003. For more information on the responsibilities of the BAAQMD.

Title V permits must contain all “applicable requirements”, monitoring requirements, recordkeeping requirements, and reporting requirements. The permit holders must submit reports of all monitoring at least every six months and compliance certifications at least every year.

The existing permit conditions are derived from previously issued permits. The review by BAAQMD includes an analysis of applicability determinations for all sources, including those that have been modified or permitted since the issuance of the initial permit. The review also includes an assessment of all monitoring in the permit for sufficiency to determine compliance.
Permit conditions may be imposed or revised as part of the annual review of the facility by the District, through a variance, an order of abatement, or as an administrative revision initiated by District staff.

An application has been filed for a permit renewal. Although the current permit expired on October 31, 2008, it continues in force until the District takes final action on the permit renewal. The public comment period on the renewal application closed on October 1, 2009 and BAAQMD is now in the process of preparing a response to comments. A permit, if one is to be issued, would be issued at the conclusion of the preparation of the response, which is likely to be in December or January. If a permit is issued, there will be public notice of the issuance.
The Bay Area Air Quality Management District and the California Air Resources Board have authority and responsibility to address air pollution violations, where they occur. The County has the responsibility and authority to evaluate air quality impacts through the CEQA process when a project proposal, such as the reclamation plan amendment for the Quarry, is submitted. When the County receives complaints regarding air pollution, the County refers them to the BAAQMD for investigation and enforcement.

The BAAQMD completed a Health Risk Assessment (HRA) under the Air Toxics Hot Spots program for the Quarry and published the HRA in November 2008. Risks are less than BAAQMD action levels for public notification (cancer risk of 10 in a million and hazard indexes of one).

The BAAQMD Compliance and Enforcement Division has conducted a review of compliance over the past year and there is no evidence of on-going non-compliance or a recurring pattern of violations. The District has not determined that the facility is out of compliance with an applicable requirement.