May 27 (Reuters) - The U.S. Supreme Court declined on

Tuesday to hear a Native American group's bid based on religious

rights to block Rio Tinto and BHP from gaining

control of Arizona land needed to build one of the world's

largest copper mines - a project situated on land long used for

Apache sacred rituals.

The justices turned away an appeal by Apache Stronghold, an

advocacy group comprised of Arizona's San Carlos Apache tribe

and conservationists, of a lower court's ruling that allowed the

federal government to swap acreage with the mining companies for

their Resolution Copper project.

A federal judge in Arizona on May 8 temporarily blocked

Republican President Donald Trump's administration from moving

forward with the land transfer pending the outcome of the appeal

to the Supreme Court.

The project is 55% owned by British-Australian mining

company Rio Tinto and 45% by Australian mining company BHP. Rio

Tinto is the project's operator. Both companies have spent more

than $2 billion on the project without yet producing any copper.

The plaintiffs sued in 2021 in Arizona federal court to

block the project, saying it violated constitutional and

statutory protections for religious rights. They argued that the

project, because it was destroy a religiously important site,

would violate the U.S. Constitution's First Amendment

protections for the free exercise of religion, as well as a

1993 federal law called the Religious Freedom Restoration Act.

The destruction of the sacred site also would violate a 1852

treaty promising that the U.S. government would protect the land

and "secure the permanent prosperity and happiness" of the

Native American tribe, the plaintiffs said.

The land swap was approved as part of a defense spending

bill signed in 2014 by Democratic President Barack Obama,

allowing the companies to exchange acreage they own for a plot

of federally owned land about 70 miles (113 km) east of Phoenix

known as Oak Flat.

The swap was conditioned on an environmental impact

statement for the mine being published by federal regulators,

which occurred in January 2021 in the waning days of Trump's

first term in office.

The site sits atop a reserve of more than 40 billion pounds

(18.1 million metric tons) of copper, a crucial component of

electric vehicles and nearly every electronic device.

The land, known as Chi'chil Biłdagoteel in the Apache

language, has long been a place where Western Apaches have

conduct sacred rituals, according to the Apache group's

historian and its lawyers at the Becket Fund for Religious

Liberty.

If the mine is built, it would create a crater 2 miles (3

km) wide and 1,000 feet (304 m) deep that would destroy that

worship site.

After a federal judge declined to halt the land transfer in

2021, Apache Stronghold filed an emergency appeal. Shortly

before former Democratic President Joe Biden's administration

was to respond to that appeal, it announced in March 2021 that

it was withdrawing the environmental impact statement, a move

that froze the land transfer.

The San Francisco-based 9th U.S. Circuit Court of Appeals in

two different rulings declined to block the transfer, mostly

recently when a panel of 11 judges ruled 6-5 against the

plaintiffs in March 2024. The panel split along ideological

lines, with six judges appointed by Republican presidents in the

majority.

Judges in the majority throughout the appeals process said

that while they were they were sensitive to the religious

concerns, they felt compelled to rule narrowly on the question

of whether the U.S. government can do what it wants with its own

land.

After Trump returned to office, the U.S. Forest Service on

April 17 said it would republish within 60 days an environmental

report needed for the Resolution Copper project land swap to

occur. A federal judge on May 9 blocked it from doing so pending

the outcome of the Supreme Court appeal.