The Yolo County Planning Commission on Oct. 9 heard a staff presentation and public comment on CEMEX’s proposed amendment to its mining and reclamation permits for its 1,902‑acre Cache Creek operation east of Interstate 505 near Madison, but did not take a final vote and was told it must re‑notice the matter for a Nov. 13 public hearing after a newspaper‑publication error.

County contract planner Heidi Chudin told commissioners the proposal would extend mining rights through 2047, increase total permitted tonnage by about 21,400,000 tons, change the maximum simultaneously disturbed acreage, and alter the configuration and timing of approved reclamation — moving some reclaimed acreage to habitat and lakes, and removing Phase 7 on the west side of I‑505 from the approved footprint. Chudin said the application is accompanied by a subsequent environmental impact report (SEIR) that tiers from the original 1996 EIR and the 2019 Cache Creek Area Plan update EIR, and staff is prepared to recommend certification of the SEIR and approval of the amended permits after the item is re‑noticed.

Why it matters: The proposal would allow continued extraction from a long‑running Cache Creek gravel operation and change how and when mined areas are reclaimed, affecting future parkway connections, habitat acreage and agricultural returns. The county’s decision also must address ongoing findings about methylmercury in off‑channel pits, a regional concern with potential human‑health and ecological implications.

Most important facts
- Applicant: CEMEX; consulting project manager Yasha Sabre and CEMEX director Robert Cutter presented the proposal and said the company is seeking a 20‑year extension of the permit term (through 2047) to mine existing approved footprints and to optimize mining for its electric wet‑mining equipment. Sabre said the proposal would not expand the overall mining footprint and that Phase 7 would be removed.
- Key technical changes described by staff and the applicant: extension of the permit term to 2047; an increase in the total permitted tonnage (~21,400,000 additional tons); a change in the assumed maximum disturbed acreage (from 126 acres at any one time in the 1996 analysis to a range of about 167–285 acres at one time); an adjusted plan for processing and settling ponds (Phase 3 proposed as a primary settling pond for process fines); and updated reclamation plans with different lake footprints, habitat features (islands and peninsulas) and an overall reclamation completion date no later than 2052.
- Net gains and public benefits: Sabre and Heidi Chudin described amendments to the project’s development agreement to add or clarify “net gains” (public benefits) including enlarged lake/perimeter habitat acreage (+~74 acres), dedications or easements for an eastern road, a Western road easement, a 40‑foot “Creekside” trail easement to create a loop trail, and dedication of a roughly 12‑acre Millsap Connector property to close a gap in the parkway/trail network. The amended development agreement would also include a monetary donation for the Cache Creek Nature Preserve and county planning updates.

Public comment and concerns
Commissioners heard a multi‑hour public comment period in which conservation groups, neighbors and Sierra Club speakers pressed a range of concerns. Key recurring themes were methylmercury in off‑channel pits, the pace and transparency of monitoring and analysis, long reclamation timeframes, and whether reclaimed lands should favor habitat/wetland restoration over lakes or agriculture.
- Scientists and environmental advocates told the commission that mercury methylation was an ongoing, programmatic concern in multiple Cache Creek pits and urged more rapid development and deployment of the county’s lake management plan and pilot tests of mitigation measures.
- CEMEX representatives and affiliated agronomists defended past reclamation work, cited monitoring data (including lower mercury readings in some pits after operational changes) and proposed pilot interventions (destratification, sand capping, oxygenation, sequestration with activated carbon, fish management) as programmatic solutions. Consultant Yasha Sabre said the operator is prepared to fund and participate in county‑led pilot testing and is ultimately responsible for addressing any pits that cannot be adequately remediated.

Technical points emphasized by speakers
- Mercury monitoring rules: Chudin and Sabre summarized Yolo County’s mining ordinance requirement (section 10‑5.517 discussed during the meeting) that established monitoring and a 5‑year monitoring window for newly permanent pits; three exceedances in five years triggers expanded analysis and development of a lake management plan. Sabre said monitoring has been underway for years and that County‑funded, programmatic lake management work is advancing.
- Depth and mining method: Sabre confirmed the project does not propose increasing maximum mining depth (the deepest mining entitlement remains 75 feet; pool depth ~60 feet above water) and that the operation uses electric dredges and conveyors; the applicant said electrified mining reduces local air emissions compared with older diesel‑driven equipment.
- Reclamation and soils: Sabre said updated three‑dimensional geologic modeling shows less available overburden/topsoil than earlier owners assumed, which reduces the acreage that can be returned to agriculture but increases the volume of marketable sand and gravel (a lower stripping ratio). CEMEX said it is performing concurrent reclamation and has already returned some areas to agriculture, citing a 2021 House Agricultural Consultants report that documented crop yields on reclaimed parcels.

Agency process and next steps
County counsel and staff told the commission that a public meeting could be held and staff and applicant presentations and comments would be part of the administrative record, but because the final public hearing notice failed to meet the 10‑day legal publication requirement for a public hearing, the commission must not take a final action today. Staff said the item will be re‑noticed for the commission’s regular Nov. 13 meeting and the county will ask the Daily Democrat to publish the final hearing notice. When the hearing is re‑noticed, staff intends to present a recommendation that the commission recommend to the Board of Supervisors: certification of the final SEIR, adoption of CEQA findings and a mitigation monitoring program, a circulation element finding, approval of mine/reclamation amendments with conditions, and authorization to execute an amended development agreement.

Votes and formal actions
No formal planning‑commission vote on the CEMEX amendments was taken at this meeting. Staff explicitly asked the commission to refrain from taking a final action because the hearing notice did not meet the legal publication requirements; the item is scheduled for a properly noticed public hearing Nov. 13.

Context and background
The CEMEX operation is 1 of 6 active Cache Creek gravel operations; the site’s key permits date to 1996 and were previously analyzed in a 1996 EIR; the current amendment is a subsequent EIR tying to the 1996 EIR and the 2019 Cache Creek Area Plan Update EIR. The county’s surface mining program contemplates development agreements and “net gains” that provide public benefits such as trails, habitat dedications and parkway links. Mercury contamination of Cache Creek is a watershed‑scale legacy issue linked to historic upstream mercury mining; the county and operators are developing an adaptive, programmatic lake management plan and pilot tests to identify feasible mitigation approaches.

What to watch
- Nov. 13, 2025: the Planning Commission’s re‑noticed public hearing (staff and applicant presentations, additional public comment and a possible recommendation to the Board of Supervisors).
- Publication and release of the most recent mercury monitoring and expanded analysis results (staff indicated 2023–24 reports were under review and expected to be released prior to Nov. 13).

Ending
The commission will accept written comments until the re‑noticed public hearing and has placed the entire SEIR and related correspondence into the administrative record. After the Nov. 13 hearing the commission may forward a recommendation to the Board of Supervisors, which holds final authority over the mining and development agreement amendments.