For background on previous coverage and history on the 1872 mining law, read our Editor's Note

Geologist Jeff Cornoyer steers a Ford van over a rocky, rutted, winding dirt road, climbing the foothills of the Santa Rita Mountains on a toasty August morning. The desert here, about 30 miles southeast of Tucson, is dotted with shade-giving oak, juniper and mesquite trees. Cornoyer stops in a natural bowl surrounded by ridges and buttes and tries to explain to his passengers -- local government officials and a journalist -- why this place should be transformed into the country's third-largest copper mine.

"The people I want to inform are the people who don't know much about the project," he says, implying that those who do know a lot about it have already made up their minds. Some, like Cornoyer, think it's a great idea. Others see it as a disaster in the making.

Cornoyer's employer, Rosemont Copper -- a Tucson subsidiary of the Canada-based Augusta Resource Corp. -- wants to spend a billion dollars to dig a half-mile-deep pit here. Rosemont promises to handle the ore and tailings in a careful way, and to continually restore the land and vegetation during the decades of the project's life. The company calls it "sustainable" mining.

Tours like this one are part of a savvy public-relations effort that includes company promises to create many high-paying jobs and even install solar panels on its offices. Copper is essential to a green economy, Cornoyer points out: Hybrid cars need more copper than conventional vehicles, and photovoltaic panels also need the element.

Nevertheless, Rosemont's proposal has sparked a typical Western-style battle over mining. Opponents, who number in the tens of thousands, worry that the mine would have environmental impacts far beyond the 995 company-owned acres in the core of the site, and on a much larger scale than the primitive mining that occurred in this area from the late 1800s up to the mid-1900s. Rosemont would have to blade 3,670 acres of federally owned desert for its operations, including disposal of tailings and other wastes. The mine might also diminish the water table, drying up neighboring creeks and springs, and damage Native American cultural sites. So environmentalists have filed lawsuits trying to stop it. Now it's become a battle over the heart and soul of this whole area.

At the center of the swirling arguments, the agency directly in charge of the federal land, the U.S. Forest Service, has studied the plan for more than two years and hopes to release a draft environmental impact statement by the end of this year. The Forest Service is trying to sort out the pluses and minuses. But the fundamental issue is the same as the one that underlies many other battles over mining: Has the decision already been made by a 138-year-old law?

With one exception, the feds have never even seriously attempted to deny a mine proposal on federal land, since the passage of the General Mining Act of 1872. Mines have been stopped by court rulings, permit delays, overwhelming local opposition, economics, regulations on pollution and so on -- but never because a federal agency simply said no. Still, Rosemont Copper sounds a little worried: A prominent message on its website insists, "The General Mining Act of 1872 continues to guarantee the ability to mine claims. ..."

Mining opponents throughout the country hope for a breakthrough here. They want the Forest Service to make history by voicing the first clear federal "no." And -- despite considerable waffling -- the agency has at least hinted that it might do so.

According to the 1872 law, "All valuable mineral deposits in lands belonging to the United States, both surveyed and unsurveyed, are hereby declared to be free and open to exploration and purchase ... by citizens of the United States."

Generally, that language has been seen as a green light for all mining on federal land. And the green light shines mostly in the West, because most federal land is in our region. Yet the legal reality is complicated. Over time, more laws and regulations have given the Bureau of Land Management and the Forest Service greater authority to shape mining proposals through issues such as water quality and endangered species. The 1976 Federal Land Policy and Management Act (FLPMA) went the furthest, giving the BLM a vague power to stop "unnecessary or undue degradation" from mining. Forest Service laws and regulations have no such language. Yet many environmentalists think the agencies can deny a high-impact mine even if it technically satisfies the environmental laws.

The mining industry says that the 1872 law effectively establishes a private property right on federal land. Once a claim is filed properly and a mineral deposit is discovered, if the feds refuse to allow mining, it's a "taking" that requires the government to compensate the claimant, says Timothy McCrum, an attorney in Washington, D.C., who represents the National Mining Association. Such compensation could total many millions of dollars, another reason why the feds have been reluctant.

The Clinton administration made the last serious effort to toughen mining regulations, but it still felt compelled to pay a Canadian company $65 million in 1996 to stop the New World gold mine, proposed for a national forest on the edge of Yellowstone National Park. The feds' legal power over that mine was murky because much of the ore body was on private land; a buyout was faster and more certain than the years of litigation that would have ensued from an attempt to say "no," according to John Leshy, the top lawyer for Clinton's Interior Department and its point man on mining regulation.

The Clintonites did try to say "no" when another Canadian company, Glamis Gold Ltd., proposed using cyanide heap-leaching to mine more than a million ounces of gold from an open pit on BLM land in the California desert. The neighboring Quechan Indian Tribe objected, arguing that the site was sacred aboriginal land, comparable to Jerusalem or Mecca. In late 2000, Leshy issued an Interior Department opinion citing the "unnecessary or undue degradation" language in FLPMA, and holding that the BLM could deny a mine to avoid "substantial irreparable harm" to important resources. Around the same time, the BLM announced that the California site was off-limits to mining.