Mexico’s government is negotiating a settlement with Vulcan Materials to permanently end limestone extraction at the Calica site in Quintana Roo, offering the company an alternative location and port-use flexibility in exchange for environmental remediation. The outcome carries weight beyond mining: the dispute has entered the USMCA joint review as one of roughly 54 US-flagged issues and prompted congressional legislation on port access, exposing how unresolved foreign investment claims can intersect with trade negotiations and infrastructure policy. A resolution would set precedent for handling environmental enforcement against foreign-owned assets in protected areas.
Mexico’s federal government is negotiating with US-based Vulcan Materials to permanently end limestone extraction in a protected natural area in Quintana Roo, President Claudia Sheinbaum said, adding that any agreement would require the company to relocate operations to an environmentally viable site and fund environmental remediation of the affected zone.
Sheinbaum said talks with Vulcan continue even as the company pursues international arbitration seeking to reopen the area to limestone mining. “They filed for arbitration, which is about to be resolved. What we are saying is, let’s see if it is feasible to reach an agreement with Vulcan,” she said.
The company’s port concession, used exclusively to ship limestone extracted from the protected area, has remained closed since Mexico halted mining at the site, Sheinbaum said. “They could not continue operating where they used to extract, because right now the port is closed. It is a concession the Mexican state granted to Vulcan for the entire port, which is a very important port for the country,” she said, according to El Universal.
Under the terms being discussed, Vulcan would be barred from any further extraction within the protected area. If limestone mining were to continue elsewhere, it would need to take place at a site deemed environmentally feasible and at reduced volumes compared with what the company has proposed. The proposed deal would also allow the port to be used for purposes beyond limestone shipments, which is its only current function. “It is still being reviewed, this has been going on for several months, whether an agreement can be reached that benefits Mexico while giving them other possibilities,” she said.
Sheinbaum said the negotiations have not been made public because no consensus has yet been reached. “If an agreement is reached, we would obviously make it public, and it would have to ensure there is no impact on the Natural Protected Area from limestone extraction and that there is environmental remediation,” she said. Multiple government agencies are working on the matter, she added, and if no deal is reached, the case would proceed to a final arbitration ruling.
The dispute centers on Calica, a limestone quarry and port facility Vulcan Materials has operated in the Yucatan Peninsula near Playa del Carmen. Mexican authorities closed the site in 2023, citing environmental permitting irregularities and damage to protected wetlands and underground water systems in the region, prompting Vulcan to pursue international arbitration against the Mexican state. SEMARNAT has maintained that the land remains Vulcan’s property and that no expropriation has occurred, according to El Universal.
Vulcan has pursued compensation through the International Centre for Settlement of Investment Disputes (ICSID) since 2022, filing for more than US$1.5 billion over what it has characterized as an illegal expropriation of its assets, according to Mexico Business News. Mexico had previously offered US$440 million for the roughly 2,000ha under concession, an offer Vulcan rejected as inadequate. The government has separately floated alternatives that would let the company use the site for tourism development rather than mining, an option consistent with the port-repurposing terms Sheinbaum described this week.
The case has also drawn attention in Washington. Beyond the legislation cited by El Universal, the US House of Representatives passed the Defense of American Property Abroad Act of 2026 in March, which would let the president deny US port access to vessels using infrastructure the bill’s sponsors describe as expropriated from American companies, a direct response to the Calica closure.
The bill followed a letter from 35 Republican lawmakers urging the Trump administration to press Mexico for a resolution. The case has also surfaced in the ongoing USMCA joint review, where it is one of roughly 54 issues the United States has flagged. Ildefonso Guajardo, Mexico’s former economy minister and a past USMCA negotiator, has said the Calica case could weigh heavily if the treaty review requires legislative ratification in Washington, citing frustration among US lawmakers over how the matter has been handled.
Vulcan has operated the Punta Venado quarry and deepwater terminal in Quintana Roo since 1986 and first sought arbitration in 2018 after Mexico revoked related port concessions. Operations were suspended in 2022 under the previous administration, which cited environmental damage from underwater limestone extraction, and the site was later designated a protected natural area. A settlement along the lines Sheinbaum outlined would resolve one of the longest-running foreign investment disputes facing Mexico’s extractive sector and could shape how future environmental enforcement actions affecting foreign-owned infrastructure are negotiated.
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