FLAGSTAFF, Ariz. (AP) – A New Mexico-based uranium producer plans to move forward with a mining operation in the western part of the state after a federal appeals court ruled Tuesday that its land is not part of Indian Country.

The full 10th U.S. Circuit Court of Appeals in Denver ruled in a 6-5 decision that the U.S. Environmental Protection Agency erred when it determined that a parcel of land near the Navajo community of Church Rock was Indian land.

The decision means that Hydro Resources Inc. can seek an underground injection control permit from the state of New Mexico rather than the EPA, which has permitting authority on tribal lands.

Hydro Resources wants to inject chemicals into the ground to release uranium and pump the solution to the surface in a process called in-situ leaching.

“I think that it's clear we were right all along, and we've been vindicated,” said Rick Van Horn, senior vice president of operations for Hydro's parent firm, Uranium Resources Inc. “That doesn't mean we're going to go ahead and do this without discussion with the other stakeholders in the community and surrounding areas.”

Hydro Resources had argued the company's land, known as Section 8, isn't legally part of the Navajo reservation because it had not been set aside for the federal government for use as Indian land. The parcel had been a part of Indian Country at one time, but was removed by federal executive order in 1911.

The Navajo Nation, which extends into Arizona, New Mexico and Utah, banned uranium mining on its lands in 2005. But companies have been trying to revive it, particularly on the eastern side of the reservation and in the Church Rock area, commonly referred to as the checkerboard of Indian and non-Indian land.

David Taylor, a natural resources attorney with the Navajo Department of Justice, said the tribe was disappointed by the court's ruling and will consider its options, including filing an appeal to the U.S. Supreme Court.

The New Mexico Environment Department granted an injection control permit to Hydro Resources in the late 1980s for the vacant property about six miles northeast of the Church Rock Chapter house. When the land status came into question, the state asked the EPA to make a determination.

The agency ruled in 2007 that the parcel was Indian land after considering the makeup of the population and the services the community receives from the Navajo Nation. A three-judge panel of the court had upheld the EPA's decision, but Hydro asked for a hearing before the full court.

Nearly 98 percent of the 2,802 residents of the Church Rock Chapter are American Indian, and most of the other residents are married to Navajos, according to the 2000 Census. Most speak Navajo and receive services through the chapter.

EPA reasoned that all of the Church Rock Chapter is Indian Country because a high percentage of the land within its boundaries is set aside for Indian use and federally superintended.

But the 10th Circuit court said Congress has not explicitly set aside Hydro's land for Indian use nor is it under federal superintendence and, therefore, cannot be considered Indian land. The court further rejected the EPA's consideration of a community of reference, which it said would turn the determination of land status into a guessing game.

“If Congress hasn't declared the land set aside for the establishment of a federally dependent Indian community, we are powerless to do so ourselves,” the court majority wrote.

Cara Peck, an EPA spokeswoman, said the agency had not yet reviewed the decision.

The court dissents argued that the majority opinion introduces confusion into the law and that a community reference should be the primary consideration when determining land status. The notion of community also should assume heightened importance when it comes to natural resources, the minority said.

“A parcel of 160 acres completely surrounded by a community of 57,000 acres should not fail to be part of that community simply because of the ownership status of that parcel,” the minority said.

The majority noted the “grave consequences” that mining operations can pose but said “it is the court's hope, no less than the hope of the dissents, that the appropriate agencies will do their assigned jobs in protecting the environment.”

Eric Jantz, an attorney for the Santa Fe, N.M.-based Environmental Law Center, which represents mining opponents, called the ruling tragic.

“Frankly, I don't think the state has much of a stake in this in terms of people with political power,” he said. “Who is going to assure that this community's water isn't going to get polluted. The federal government, the EPA is going to be a much better guardian of that than the state.”