When mining companies started calling tribal offices last year, Navajo President Joe Shirley Jr. issued an edict to employees: Don't answer any questions. Report all contacts to the Navajo attorney general.

Decades after the Cold War uranium boom ended, leaving a trail of poisonous waste across the Navajo Nation, the mining industry is back, seeking to tap the region's vast uranium deposits once again.

Companies are staking claims, buying mineral rights and applying for permits on the edge of the tribal homeland. They make no secret of their desire to mine within the reservation as well.

That prospect has turned neighbor against neighbor and touched off legal, political and financial maneuvering far from Navajo lands.

Fifty years ago, a nuclear arms race propelled the search for uranium. Today, the driving force is the quest for new sources of energy. China and India are building nuclear reactors at a rapid pace to fuel their growing economies, and the Bush administration is pushing to expand nuclear energy in this country to reduce U.S. dependence on foreign oil.

With demand increasing, the price of uranium has climbed to more than $60 a pound. Six years ago, it was as low as $7.

Mining companies are extracting uranium in Texas, Wyoming and Nebraska, and are taking steps to mine in Colorado.

But Navajo country, covering some 27,000 square miles in Arizona, New Mexico and Utah, is the biggest prize of all — "the Saudi Arabia of uranium," in the words of Mark Pelizza, a vice president of Uranium Resources Inc.

A subsidiary of the Texas-based company holds a Nuclear Regulatory Commission license to mine in and around Crownpoint, a crossroads town of 3,000 Navajos that sits on the largest known undeveloped uranium deposit in the U.S.

URI officials are seeking permission to begin mining on a test basis in the nearby township of Church Rock, N.M., in 2008. If results there convince regulators that the project is environmentally sound, the company will be allowed to start operations in Crownpoint.

Mining in both places is expected to yield 42 million pounds of uranium over 20 years — worth more than $2.5 billion at today's prices.

Two Canadian firms — Strathmore Minerals Corp. and Energy Metals Corp. — are also laying the groundwork for mining.

Altogether, the three companies have acquired rights to tens of thousands of acres just outside the reservation's southeast boundary. URI alone has invested more than $25 million.

Mining executives say they plan to extract uranium from underground rock formations through an environmentally benign chemical process. There will be no blasting, no unsightly pits and no lasting contamination, they say.

Unconvinced, the tribal council last year passed a ban on mining or processing uranium in "Navajo Indian country," a term that embraces both the reservation and neighboring communities such as Crownpoint and Church Rock that participate in tribal government.

Federal courts have recognized "Indian country" as extending beyond the reservation's boundaries, but the ban seems destined to be challenged in court.

After the measure took effect in April 2005, mining concerns kept calling the Navajo capital, Window Rock, Ariz., hoping to secure support for their projects. So Shirley signed Executive Order 02-2005, which instructs tribal employees to avoid any "communications with uranium company representatives."

The directive infuriated mining executives. "You tell me, what kind of a democracy is that?" asked John DeJoia, a Strathmore vice president. "They've got tremendous resources out there. They're a very poor nation. That could change."

Robert McNair, director of capital projects for Dejour Enterprises Ltd., a Canadian energy company, asked state officials for help. He reached Derrith Watchman-Moore, New Mexico's deputy environment secretary.