The Supreme Court on Tuesday rejected a request from some members of the San Carlos Apache Tribe to block a massive proposed copper mine that they say will destroy a holy site in Arizona known as Oak Flat.

A majority of the court denied the petition, but in a dissent joined by Justice Clarence Thomas, Justice Neil Gorsuch said he would have granted the petition. Justice Samuel Alito recused himself from considering the case.

Gorsuch in his dissent called the decision a “grave mistake” and said the case “meets every one of the standards we usually apply when assessing petitions for certiorari: The decision below is highly doubtful as a matter of law, it takes a view of the law at odds with those expressed by other federal courts of appeals, and it is vitally important. Before allowing the government to destroy the Apaches’ sacred site, this Court should at least have troubled itself to hear their case.”

Apache Stronghold had called on the Supreme Court to block the project, arguing it would violate the Religious Freedom Restoration Act, which protects their right to worship at the sacred site.

The group, alongside the Becket Fund for Religious Liberty, had warned the Resolution Copper mine would transform holy land into a 2-mile-wide and 1,100-foot-deep crater.

The site — known as Oak Flat, or Chi’chil Biłdagoteel in Apache — consists of a vast grove of Emory oaks sacred to the tribe , where some go to pray, hold ceremonies and collect acorns for cooking. It’s now part of the Tonto National Forest about 60 miles east of Phoenix, where the Forest Service currently has a campground.

The Trump administration has said it intends to complete an environmental impact statement for the mine. Once it’s released, the land exchange that accelerates Resolution Copper must happen within 60 days.

The land swap would allow the federal government to transfer thousands of acres of public land in Arizona, including the Oak Flat site, to the mining company, advancing construction of the copper mine. The deal was originally included in the 2014 National Defense Authorization Act and championed by the late Republican Sen. John McCain of Arizona.

Attorneys for Apache Stronghold brought their challenge to the Supreme Court after the 9th U.S. Circuit Court of Appeals declined to reconsider the case last year. The appeals court in a 6-5 ruling affirmed a lower court’s denial of Apache Stronghold’s request for a preliminary injunction against the government’s transfer of the land to Resolution Copper.