Archive | Resources RSS for this section

Arizona Copper Creek Mine by Redhawk

About Us Our Property Investor Resources Media News Contact Us Copper Creek Description & Location Geology 2007-2012 Drill Program Mineral Resource Estimate Property History 2010 Scoping Study Technical Reports Property Map Copper Creek Redhawk’s Copper Creek Property is located 75 road miles northeast of Tucson and 15 miles northeast of San Manuel, in an area well situated in regard to […]

Redhawk Resources Announces Framework for Copper Creek Pre-Feasibility Study

RELATED QUOTES Symbol Price Change RDK.TO 0.485 0.00 VANCOUVER, BRITISH COLUMBIA–(Marketwire -03/26/12)- Redhawk Resources, Inc. (“Redhawk” or the “Company”) (TSX:RDK.TO – News)(OTCQX: RHWKF.PK – News)(FFRANKFURT:QF7.F – News) is pleased to announce the framework for a NI 43-101 Pre-feasibility Study (“PFS”) on its 100% owned Copper Creek, Arizona project to be led by KD Engineering of Tucson, Arizona. An updated NI 43-101 resource […]

Glencore’s CEO Says Rival Mining Chiefs ‘Really Screwed Up’

By Jesse Riseborough – Feb 26, 2013 10:09 AM MT Glencore International Plc (GLEN)’s billionaire Chief Executive Officer Ivan Glasenberg criticized his recently departed mining CEO peers for swamping the industry with mines and new production that crimped profits. “The big guys really screwed up,” Glasenberg, 56, who runs the world’s largest publicly traded commodities supplier, told investors […]

Plasma Gasification Raises Hopes of Clean Energy From Garbage

By RANDY LEONARD

 

David Robau tours the country promoting a system that sounds too good to be true: It devours municipal garbage, recycles metals, blasts toxic contaminants and produces electricity and usable byproducts — all with drastic reductions in emissions.

Mr. Robau, an environmental scientist for the Air Force, has been promoting a method that was developed with the Air Force to dispose of garbage with neither the harmful byproducts of conventional incineration nor the environmental impact of transporting and burying waste. It is one of several innovative techniques that the United States military has been researching to provide alternatives to the open-pit burns that some veterans of the Iraq and Afghanistan wars say have made them ill.

Already some waste companies and cities like New York have shown an interest in technology similar to what Mr. Robau has been promoting, known as plasma arc gasification. Proponents say the process can break chemical bonds and destroy medical waste, PCBs (polychlorinated biphenyls), asbestos and hydrocarbons, some of which can be hazardous if disposed of in landfills or traditional mass-burn incinerators.

Still, some environmentalists are leery. They say the ability to fully dispose of waste will discourage recycling and the development of renewable products, and the gasification will still result in toxic substances like dioxins.

Mr. Robau maintains that the process is earth-friendly. “This is not incineration,” he said. “This is gasification, so it’s a lot cleaner, a lot better for the environment.”

Mr. Robau, who also heads a nonprofit organization based in Gulf Breeze, Fla., has overseen testing of the small-scale plasma arc gasification system, which cracks complex molecules into simple elements using energy as intense as the sun’s surface, making fuel for about 350 kilowatts of electricity from about 10 tons of garbage each day, enough to run the system.

The system has been hard at work in a 6,400-square-foot building at Hurlburt Field Air Force base in Florida’s panhandle. A mechanical shredder cuts household garbage into pieces no bigger than two inches. An airtight auger feeds the waste into an oxygen-poor gasification chamber, where temperatures reach more than 9,000 degrees.

In an instant, wood disintegrates, plastics turn to gas. Bits of metal and glass fall into a molten pool.

From two graphite electrodes, an arc of electricity leaps about a foot to the molten slag, producing a cloud of ionized particles known as plasma, which heats the chamber. Most heavier metals settle to the bottom of the pool, below a layer of liquid silica and other oxides. The metals are removed, cooled and used for steel or other products.

“Effectively, 100 percent of all the metals on the base are being recycled,” Mr. Robau said.

The liquid oxides are removed and form a glassy solid when cooled. The slag traps contaminants like errant lead molecules and other heavy metals in a vitreous matrix that takes up 1 percent of the volume of the original waste, Mr. Robau said, a tenth of the volume left over after traditional incineration.

The vitrified component meets standards for disposal and may even be suitable for use as a construction aggregate, according to Mr. Robau and other industry professionals.

In the chamber, organic gases break down into hydrogen and carbon monoxide — the components of a fuel called synthesis gas, or syngas — which exits the furnace.

The gas passes through a plasma torch polisher, which breaks down remaining complex molecules and soot.

Injected water cools the syngas to less than 200 degrees. The extreme temperature of the plasma followed by quick cooling inhibits the formation of dioxins and furans (another organic compound), according to Mr. Robau and other industry experts.

The lack of dioxin creation would be a benefit over traditional incinerators and other types of gasifiers, in which lower temperatures and incomplete burning result in toxic compounds.

Emissions rules forced a 99 percent cut in dioxin and furan emissions and a 96 percent reduction in mercury from traditional incinerators between 1990 and 2005, according to the Environmental Protection Agency. However, companies have to dispose of the toxic ash filtered from mass-burn facilities.

After water quenches the gas in the Hurlburt system, stripping processes produce sodium bisulfate and hydrochloric acid, which can be sold, Mr. Robau said.

The gas passes through three types of filters to catch remaining impurities. The resulting syngas is as clean or cleaner than natural gas, and the system produces less than half the nitrogen oxides and 5 percent of the sulfur oxides and mercury of a traditional incinerator, Mr. Robau said. The Air Force uses the syngas to produce enough electricity to power the system.

Companies have used plasma arc technology in steel refining for more than a century. Some small-scale plasma gasifiers are specialized to process materials like asbestos or medical waste.

In Japan, a plasma facility originally designed to zap residue from automobile shredding now handles up to 150 tons of municipal solid waste each day in the city of Utashinai. And construction on a plant of similar size, designed to process industrial waste and wood chips, wrapped up this summer in Morcenx, in southern France.

Companies have been eying plasma gasification of municipal waste with eager hopes, but until recently financing has lagged. Plasma facilities are expensive, and the energy-hungry arcs and torches can consume half of the generated electricity. On the other hand, the systems can also handle medical and hazardous waste, which can command two to four times the fees associated with municipal waste.

“The problem has been over the years trying to find that economic sweet spot,” said Joe Vaillancourt, who evaluates newer technologies for Waste Management, a $15.4 billion company with headquarters in Texas.

In the past five years, with increased interest in energy independence and sustainability, venture capitalists and companies have financed testing of small-scale systems, including a 25-ton system built and run by InEnTec in Arlington, Ore., Mr. Vaillancourt said. Waste Management now holds an equity stake in InEnTec.

Last month the Agriculture Department announced a conditional $105 million loan guarantee for Fulcrum BioEnergy to build a much larger system outside Reno, Nev. It will use three InEnTec plasma melters to process 400 tons of garbage a day, an unprecedented scale for a plasma municipal waste facility, said Mr. Vaillancourt and others in the industry. Fulcrum plans to create ethanol from the syngas, and expects the Reno plant to be running in 2014.

New York City, too, is looking for innovative technology to deal with some of the city’s waste. In March, the Bloomberg administration requested proposals to build a facility that would use newer techniques like plasma gasification oranaerobic digestion to process as much as 900 tons of garbage a day.

“New Yorkers want their trash to be handled in an environmentally friendly way,” said Caswell F. Holloway, deputy mayor for operations. “Anything would be better than putting it in the ground.” The city is reviewing the proposals.

Still, some environmental groups, like the Sierra Club and the Global Alliance for Incinerator Alternatives, lump these techniques in with traditional incinerators, claiming that they still produce dioxin. They also oppose renewable energy credits for these facilities.

Allen Hershkowitz, a scientist with the Natural Resources Defense Council, said he believed there was a place for waste-to-energy operations, but only after recycling and composting programs had been maximized.

He said he still believed that communities could reach recycling rates of 60 to 70 percent. In his view it is premature for a city like New York, with a recycling rate of about 15 percent, to be considering setting up a new waste facility. “They’re not even at the point where they should be thinking about waste-to-energy,” Mr. Hershkowitz said.

<nyt_correction_bottom>

This article has been revised to reflect the following correction:

Correction: September 12, 2012

 

An article on Tuesday about the plasma arc gasification method of waste disposal misstated part of the name of the organization with which Allen Hershkowitz, a scientist who said he believed that New York City’s low recycling rate makes its interest in waste-to-energy technology premature, is affiliated. Mr. Hershkowitz is with the Natural Resources Defense Council, not the National Resources Defense Council.

 

<nyt_update_bottom>

Court Forces a Rethinking of Nuclear Fuel Storage

Pool photo by Shawn Rocco

Spent fuel storage pools at the Shearon Harris nuclear plant in New Hill, N.C., operated by Progress Energy, seen last month.

By 

WASHINGTON — The Nuclear Regulatory Commission acted hastily in concluding that spent fuel can be stored safely at nuclear plants for the next century or so in the absence of a permanent repository, and it must consider what will happen if none are ever established, a federal appeals court ruled on Friday.

The Indian Point nuclear power plant on the banks of the Hudson River in Buchanan, N.Y. The initial 40-year licenses at the two operating reactors there expire in 2014 and 2016.

In a unanimous opinion, a three-judge panel of the Court of Appeals for the District of Columbia said that in deciding that the fuel would be safe for many decades, the commission did not carry out an analysis of individual storage pools at reactors across the country, treating them generically instead. The commission also did not adequately analyze the risk that cooling water will leak from the pools or that the fuel will ignite, the court wrote.

The commission has relied on its conclusion that spent fuel rods can be safely stored at plants to extend the operating licenses of dozens of power reactors in recent years and to license four new ones.

The plaintiffs — four states, including New York, environmental groups and an American Indian organization — declared victory, although the precise implications were not clear. Still, it appeared that the commission would have to prepare and publicly defend an assessment that storage for many decades or even indefinitely did not entail large risks.

In the 1980s, Congress directed the Department of Energy to prepare a plan for creating a national repository at Yucca Mountain, a volcanic structure in the Nevada desert about 100 miles from Las Vegas. But that plan, decades behind schedule, was shelved in 2010 by President Obama, who had promised in his 2008 campaign to kill it if elected.

Some Republican lawmakers are now hoping to revive the idea of storage at Yucca but would face determined opposition, above all from the leader of the Senate’s Democratic majority, Harry Reid of Nevada.

“The commission apparently has no long-term plan other than hoping for a geologic repository,” the appeals court wrote.

If the federal government “continues to fail in its quest” to find a place for spent nuclear fuel, then the material “will seemingly be stored on site at nuclear plants on a permanent basis,” the court said, and the commission will have to size up the environmental risks of this.

Failing to establish a repository is “a possibility that cannot be ignored,” the judges said.

A spokesman for the regulatory commission said that its lawyers were studying the ruling and that they would have no immediate comment.

New York State officials said they hoped the ruling meant that the commission would have to complete a sweeping analysis of waste storage at reactors before extending the licenses of the Indian Point reactors in Westchester County, which Gov. Andrew M. Cuomo wants shut down. The initial 40-year licenses at the two operating reactors there expire in 2014 and 2016.

John J. Sipos, a state assistant attorney general, said the safety rule that was at issue in the case had effectively taken “the waste issue off the table” in license renewals in recent years.

“We think that at Indian Point and other facilities going through license renewal, those issues will be back on the table,” Mr. Sipos said. He added that the commission’s analysis will have to cover whether waste should be moved out of the spent fuel pools and into sealed steel-and-concrete capsules called dry casks. The analysis will also have to address what the environmental impact of the casks will be if no burial site is built, he said.

A spokesman for Entergy, which owns the reactors at Indian Point, around 40 miles north of Midtown Manhattan, said, “There is no reason to believe this issue will affect the current schedule for license renewal proceedings.”

The industry’s main trade association, the Nuclear Energy Institute, said it was disappointed by the ruling but urged the commission “to act expeditiously to undertake the additional environmental analysis.” It would not comment on whether any licenses would be affected.

Geoffrey H. Fettus, a lawyer at the Natural Resources Defense Council who argued the case, said that because of Friday’s ruling, “this is the first instance where the long-term implications of our nuclear waste disposal policy will have to be given a hard public look.”

Opponents of nuclear power have long cited the lack of a firm plan for a waste burial place in opposing license extensions for reactors. In the meantime, the terrorist attacks of Sept. 11, 2001, and the earthquake and tsunami that hit the Fukushima Daiichi nuclear plant in Japan last year have sharpened a debate about how the fuel is stored now.

Most of it is kept in deep pools made of steel-reinforced concrete and lined with stainless steel, in water that is monitored and filtered. At most plants those pools have been packed full, and some older fuel has been moved into dry casks.

Such casks have survived floods and earthquakes without apparent damage, and some experts have called for thinning out the pools and filling up more casks. The commission has said that either method is acceptable.

The fear is that if a pool leaked or if cooling failed and the pool boiled dry, the fuel could catch fire, although many experts doubt this is possible.

In its ruling on Friday, the court said the commission had reached its conclusions by examining past leaks. But that history “tells us very little about the potential for future leaks or the harm such leaks might portend,” it wrote.

WaterClean drinking water for everyone, everywhere

Nearly 80 percent of disease in developing countries is linked to bad water and sanitation; now scientists have developed a simple, cheap way to make water safe to drink, even if it is muddy

Nearly 80 percent of disease in developing countries is linked to bad water and sanitation. Now a scientist at Michigan Technological University has developed a simple, cheap way to make water safe to drink, even if it is muddy.

It is easy enough to purify clear water. The solar water disinfection method, or SODIS, calls for leaving a transparent plastic bottle of clear water out in the sun for six hours. That allows heat and ultraviolet radiation to wipe out most pathogens that cause diarrhea, a malady that kills 4,000 children a day in Africa.

It is a different story if the water is murky, as it often is where people must fetch water from rivers, streams, and boreholes. “In the developing world, many people don’t have access to clear water, and it’s very hard to get rid of the suspended clay particles,” says Joshua Pearce, an associate professor of materials science and engineering. “But if you don’t, SODISdoesn’t work. The microorganisms hide under the clay and avoid the UV.”

To purify your water, you first have to get the clay to settle out, a process called flocculation. A Michigan Technological University release reportsthat Pearce, working with student Brittney Dawney of Queen’s Universityin Ontario, discovered that one of the most abundant minerals on Earth does this job very well: sodium chloride, or simple table salt.

Salt is inexpensive and available almost everywhere. And it doesn’t take very much to make muddy water clear again.

“The water has a lower sodium concentration than Gatorade,” Pearce says. This would still be too much salt to pass muster as American tap water, but American tap water is not the alternative.

“I’ve drunk this water myself. If I were somewhere with no clean water and had kids with diarrhea, and this could save their lives, I’d use this, no question,” he says.

Salt works best when the suspended particles are a type of clay called bentonite. The technique doesn’t work as well with other kinds of clay. However, by adding a little bentonite with the salt to water containing these different clays, most of the particles glom together and settle out, creating water clear enough for SODIS treatment.

Pearce and Dawney are running more tests on water containing various types of clays, and they are also investigating different soil types across Africa to see where their methods might work the best.

— Read more in “Optimizing the Solar Water Disinfection (SODIS) Method by Decreasing Turbidity with NaCl,” Journal of Water, Sanitation, and Hygiene for Development (forthcoming, June 2012)

Wind turbine to harvest energy and water from desert air

Eolewater's WMS1000 wind-driven water-harvesting system uses on-board cooling units to chi...

Eolewater’s WMS1000 wind-driven water-harvesting system uses on-board cooling units to chill the air until its moisture condenses

Image Gallery (5 images)

Affordable Solar Energy – www.SolarCity.com/SolarSavings
Power Your Home with Sunshine. The Cleaner and Affordable Way to Save!
Cox® Communications in AZ – CoxValue.com/Bundle
Cox Bundles. $25 each. No Contract. Order Exclusive Web Offer Today!
Chiller Systems – LegacyChillers.com/WaterChillers
Low Prices & Free Shipping. Order Today & Save. Call or Chat Live.
Arizona Solar Power – Solar-Arizona.org
75% Lower Bills. 40% AZ Rebates! Call us 24hr 888-481-8665

Ads by Google

We’ve all seen ice cold glasses and bottles dripping with condensation after cooling water vapor in the air, and though grabbing water out of thin air is not new, it took French inventor and Eolewater founder Marc Parent’s umpteenth emptying of his air conditioner’s condensate to envision harvesting atmospheric moisture on acommercial scale using wind turbines. After years of designs and prototypes, his proof-of-concept device, essentially a wind-powered refrigeration/condensation/filtration unit, was put in operation in the dry desert air of Abu Dhabi last October where it’s been reliably extracting 130-200 gal (approx. 500-800L) of clean, fresh water a day ever since.

“Access to drinking water is a condition for life and cannot be considered a luxury reserved to developed countries,” Parent said. “Humanity cannot ignore the pain of those deprived of water access and has to find new solutions.” The turbine units are not designed solely for desert-use. Being self-contained makes them suitable for any isolated areas that lack the infrastructure for water and/or electricity distribution, including islands, disaster areas, etc.

Housed in a 19.7 ft x 6.5 ft (6 m x 2 m) nacelle, Eolewater’s fifth generation WMS1000 water condenser system sits atop a 78 ft (24m) mast and is powered by a 30 kW wind turbine (minimum 15 mph (24 kph) wind speed required) with a 42 ft (13 m) diameter rotor. Since our atmosphere contains a reasonable amount of water (even the Sahara desert has an average relative humidity of around 25%), it’s simply a matter of using the wind to generate electricity for the on-board cooling units to chill the air until its moisture condenses out.

Once the water is collected, it is filtered and sent to stainless steel tanks for storage – simple as that. Apparently, the units are so durably built that, with routine maintenance, it’s estimated they’ll last up to 30 years. In areas where sun abounds but the winds are unreliable, Eole has also designed the WMS-30kW Solar Panel to drive the condensation/filtration equipment. For the millions living in or adjacent to deserts and drought-prone areas around the world, that’s welcome news, indeed.

Source: Eolewater via Treehugger

Growth Prospects for Uranium Stir Concerns

By 

HOBSON — At the back of a South Texas uranium processing facility, a few dozen black container drums stood outside, waiting to be shipped. Each was filled with about $50,000 worth of yellowcake, a powdery substance created from raw uranium.

Axel Gerdau for The Texas Tribune

This uranium processing plant in Hobson hopes to increase the 200,000 to 250,000 pounds of yellowcake it produces each year.

Axel Gerdau for The Texas Tribune

Yellowcake, made from raw uranium.

“That’s pretty close to a Lexus in every drum,” said Gregory Kroll, the superintendent of the site, which is run by the Uranium Energy Corporation, based in Corpus Christi. The company mines the uranium in Duval County and brings it here for processing, before sending it on to a plant in Illinois, where it is further refined.

Company officials hope that the Hobson plant will increase its yellowcake production, now at 200,000 to 250,000 pounds per year, far below the plant’s capacity. Uranium has been mined in Texas for decades, but companies see a potential hike in demand for their product. They are ramping up for a new push, despite concerns from environmental groups that past operations have not been sufficiently cleaned up and pose a threat to aquifers that people drink from.

Last year, the Texas Railroad Commission granted five new permits for uranium exploration in Texas, more than in any year since 2007. Two more exploration permits are being processed, one in Bee County and the other in Goliad County and both sought by Uranium Energy.

Uranium companies’ enthusiasm may seem surprising, given the shock waves caused by last year’s nuclear disaster in Japan. Even Texas’ two nuclear plants felt the jolt: both had been planning expansions, but that talk has subsided.

But companies like Uranium Energy are anticipating increased long-term demand for nuclear power from places like China and Saudi Arabia. Also, a big source of supply for American power plants is set to end next year, with the expiration of a program in which uranium from old Russian warheads is diluted and sent to power plants in the United States.

Dale Klein, the associate director of the Energy Institute at the University of Texas at Austin and former chairman of the Nuclear Regulatory Commission, said the Russian warhead program could be renewed. Nonetheless, he said, “I think the demand for uranium will continue to increase.”

Texas, Mr. Klein added, is a “key player, but they’re not a big player” in global uranium production, which is led by Kazakhstan, Canada and Australia.

Only six uranium mines are operating in the United States, according to the Energy Information Administration. Two are in Texas, in Brooks and Duval Counties, two are in Wyoming, and one each is in Nebraska and New Mexico. Texas has less than one-tenth of the reserves of Wyoming, the leading state, according to the latest energy agency data, from 2008.

South Texas has long been a hub for uranium mining. The metal, derived from ancient volcanoes, is found in a soluble form in aquifers. Often it lies near oil and gas deposits, a result of the way both substances have traveled through fissures in the ground. (Indeed, some of the mining and processing facilities lie in the booming Eagle Ford Shale.)

Today all mining in Texas is done through a process called in-situ leaching, in which oxygenated water is sent into the aquifers to dissolve the uranium. The fluid that comes back up runs through resin pellets that clamp onto the uranium. The resin, which is reusable, is transported to facilities like Hobson, which remove the uranium and turn it into yellowcake.

In past decades, open-pit mining was the norm, but that stopped in Texas in 1992, according to Kevin Raabe, an official with Rio Grande Resources. The old open-pit mines are supposed to be “reclaimed,” or filled with materials like clean soil that cover the uranium. Mr. Raabe’s company manages an old open-pit site in Hobson where Chevron began mining uranium in the 1970s. Cows graze over where the pit used to be.

Some residents seem unperturbed by the old mine sites around South Texas.

“We have a reclaimed uranium pit on our property,” said Jane Mutz, a Falls City resident with land near Fashing. “We eat the fish out of the tank,” she added, referring to a large watering hole.

But Richard Lowerre, an Austin lawyer with Lowerre, Frederick, Perales, Allmon & Rockwell, has been fighting uranium companies for decades and said that many former open-pit mining areas remain unsafe for human habitation.

As for the modern in-situ mines, the companies are supposed to restore the quality of the aquifer to its condition before the mining began, according to the Texas Commission on Environmental Quality, which issues mining licenses and regulates the operations, by designation of the Nuclear Regulatory Commission. (The Railroad Commission’s permits cover exploratory wells only.)

Mr. Lowerre and other critics say that companies never do a full cleanup of aquifers.

A 2009 report by the United States Geological Survey found that most Texas uranium well fields contained a higher concentration of uranium after mining was completed than before.

Mr. Raabe acknowledged challenges, but he said that the water was nonpotable in any case. “Does it really matter if there’s 0.3 parts per million uranium in the water before you started mining and when you ended up, it ends up at 0.8?” he said. Both numbers, he said, are “orders of magnitude above the drinking water standards.”

The industry also says that the uranium is essentially immobile — a point contested by environmentalists, who say it can migrate very slowly.

“In the 40 years this industry has been active, there’s never been a well, private or public, that’s been harmed by this process,” said Harry Anthony, chief operating officer for Uranium Energy Corp.

George Rice, a San Antonio-based hydrologist who has testified for opponents of a uranium operation in Kleberg County, said that might be the case but that the issue is inadequate monitoring. “If contamination has occurred, they haven’t looked for it,” he said of mining companies.

In Kleberg County, the legal wrangling centers on restoration of a site called the Kingsville Dome, which has been mined periodically over the years but is currently not operating. The county, represented by Mr. Lowerre’s law firm, and the mining company, Uranium Resources Inc., are disputing issues related to the standards the company must meet for cleanup. A trial resumes in early May.

Mark Pelizza, a senior vice president of U.R.I., said the company, which could resume mining on the site, would “certainly like to see the issue revolved.”

Another fight is in Goliad County, where Mr. Anthony’s company wants to begin mining uranium in the Evangeline Aquifer but has run into opposition. The aquifer is the county’s sole water source and “could be significantly harmed” by uranium mining, according to a letter last month to the Environmental Protection Agency from a group that includes the Goliad County Groundwater Conservation District and Blackburn & Carter, a Houston law firm. Mr. Anthony said that is the “same old stories we’ve heard for 40 years, and none of it is ever true.”

The E.P.A. is considering an “aquifer exemption” permit for the Goliad County operation — something all in-situ uranium mines need before proceeding. Mr. Anthony complained that the requirements from the E.P.A., which has been studying the permit since Texas officials approved it last year, are unprecedented.

The E.P.A. is also considering new national standards for monitoring of in-situ sites.

 

kgalbraith@texastribune.org

Uranium Mines Dot Navajo Land, Neglected and Still Perilous

Joshua Lott for The New York Times

An abandoned uranium mine on the Navajo reservation in Cameron, Ariz., emits dangerous levels of radiation.

By LESLIE MACMILLAN

CAMERON, Ariz. — In the summer of 2010, a Navajo cattle rancher named Larry Gordy stumbled upon an abandoned uranium mine in the middle of his grazing land and figured he had better call in the feds. Engineers from the Environmental Protection Agency arrived a few months later, Geiger counters in hand, and found radioactivity levels that buried the needles on their equipment.

Joshua Lott for The New York Times

Lucy Knorr says her father’s death was related to his work at the mine.

Joshua Lott for The New York Times

Larry Gordy discovered the mine on his land in 2010, but it has not been cleaned up yet.

Joshua Lott for The New York Times

At a mine in Cameron, Ariz., the radioactivity levels exceeded Geiger counters’ scales.

The abandoned mine here, about 60 miles east of the Grand Canyon, joins the list of hundreds of such sites identified across the 27,000 square miles of Navajo territory in Arizona, Utah and New Mexico that are the legacy of shoddy mining practices and federal neglect. From the 1940s through the 1980s, the mines supplied critical materials to the nation’s nuclear weapons program.

For years, unsuspecting Navajos inhaled radioactive dust and drank contaminated well water. Many of them became sick with cancer and other diseases.

The radioactivity at the former mine is said to measure onemillion counts per minute, translating to a human dose that scientists say can lead directly to malignant tumorsand other serious health damage, according to Lee Greer, a biologist at La Sierra University in Riverside, Calif. Two days of exposure at the Cameron site would expose a person to more external radiation than the Nuclear Regulatory Commission considers safe for an entire year.

The E.P.A. filed a report on the rancher’s find early last year and pledged to continue its environmental review. But there are still no warning signs or fencing around the secluded and decaying site. Crushed beer cans and spent shell casings dot the ground, revealing that the old mine has become a sort of toxic playground.

“If this level of radioactivity were found in a middle-class suburb, the response would be immediate and aggressive,” said Doug Brugge, a public health professor at Tufts University medical school and an expert on uranium. “The site is remote, but there are obviously people spending time on it. Don’t they deserve some concern?”

Navajo advocates, scientists and politicians are asking the same question.

The discovery came in the midst of the largest federal effort to date to clean up uranium mines on the vast Indian reservation. A hearing in 2007 before the House Committee on Oversight and Government Reform led to a multiagency effort to assess and clean up hundreds of structures on the reservation through a five-year plan that ends this year.

Yet while some mines have been “surgically scraped” of contamination and are impressive showpieces for the E.P.A., others, like the Cameron site, are still contaminated. Officials at the E.P.A. and the Department of Energy attribute the delay to the complexity of prioritizing mine sites. Some say it is also about politics and money.

“The government can’t afford it; that’s a big reason why it hasn’t stepped in and done more,” said Bob Darr, a spokesman for the Department of Energy. “The contamination problem is vast.”

If the government can track down a responsible party, he said, it could require it to pay forremediation. But most of the mining companies that operated on the reservation have long since gone out of business, Mr. Darr said.

To date, the E.P.A., the Department of Energy and other agencies have evaluated 683 mine sites on the land and have selected 34 structures and 12 residential yards for remediation. The E.P.A. alone has spent $60 million on assessment and cleanup.

Cleaning up all the mines would cost hundreds of millions of dollars, said Clancy Tenley, a senior E.P.A. official who oversees the uranium legacy program for the agency in the Southwest.

Some say the effort has been marred by bureaucratic squabbles and a tendency to duck responsibility. “I’ll be the first to admit that the D.O.E. could work better with the E.P.A.,” said David Shafer, an environmental manager at the energy agency.

Determining whether uranium is a result of past mining or is naturally occurring is “a real debate” and can delay addressing the problem, Mr. Shafer said. He cited seepage of uranium contaminants into the San Juan River, which runs along the boundary of the reservation, as an example. “We need to look at things like this collectively and not just say it’s E.P.A.’s problem or D.O.E.’s problem,” he said.

E.P.A. officials said their first priority was to address sites near people’s homes. “In places where we see people living in close proximity to a mine and there are elevated readings, those are rising to the top of the list for urgent action,” Mr. Tenley said.

Agency officials said they planned a more thorough review of the Cameron site — which still has no warning signs posted — within the next six months.

Meanwhile, Navajos continue to be exposed to high levels of radioactivity in the form of uranium and its decay products, like radon and radium. Those materials are known to cause health problems, including bone, liver, breast and lung cancer.

Lucy Knorr, 68, of Tuba City, Ariz., grew up near the VCA No. 2 mine operated by the Kerr-McGee Corporation, now defunct. Her father, a former miner, died of lung cancer at age 55 in 1980, and her family received a payout of $100,000 under the Radiation Exposure Compensation Act, a law that was enacted after her mother hired a lawyer and testified before Congress.

The program has awarded $1.5 billion for 23,408 approved claims since it was enacted in 1990.

Ms. Knorr’s father was one of hundreds of Navajos who did not wear protective gear while working in the mine. “He’d wash at a basin outside” after leaving the mine, she said, “and the water would just turn yellow.”

The government has been successful in tracking down and holding some former mining companies accountable. The E.P.A. is requiring that General Electric spend $44 million to clean up its Northeast Church Rock Mine, near Gallup, N. M. Chevron is paying to clean up the Mariano Lake Mine, also in New Mexico.

When the government cannot locate a responsible party, which is most often the case, the E.P.A. and the Department of Energy work with the tribal authorities to reach cleanup decisions. In general, the E.P.A. handles mines, while the Energy Department is responsible for the mills where the ore was processed and enriched.

One of the Department of Energy’s biggest priorities is a billion-dollar uranium mine cleanup that is under way in Moab, Utah, and that received $108 million in federal stimulus money and the backing of nine congressmen.

Some Navajo officials point out that Interior Secretary Ken Salazar signed a 20-year moratorium on new uranium and other hard-rock mining claims on one million acres of federal land around the Grand Canyon in January, saying it was needed to preserve the mile-deep canyon and the river that runs through it. The mining industry is challenging that decision in court.

But the Navajo Nation, considered a sovereign government entity, has not gotten similar treatment from the federal government for its land, some of its officials say. The nation has asked for $500 million for mine cleanup, but the money has not materialized, said Eugene Esplain, one of two officials with the Navajo E.P.A. responsible for patrolling an area the size of West Virginia.

Taylor McKinnon, a director at the Center for Biological Diversity, an environmental group that worked to halt new mining claims near the Grand Canyon, said the Cameron site was the worst he had seen in the Southwest. He has even seen cow droppings near the mine, he said, an indication that cattle are grazing there. And “people are eating those livestock,” he said.

Ronald Tohannie, a project manager with the Navajo advocacy group Forgotten People, said the locally grown beef was tested at the slaughterhouse, but not for the presence of radioactive substances like uranium.

When E.P.A. officials in the California office overseeing the region were asked to accompany a reporter to the Cameron mine site, they countered with an offer to visit the Skyline Mine in Utah, on the northern boundary of the reservation in Monument Valley, where a big federal cleanup was completed last October.

The onetime mine, atop a 1,000-foot mesa, provides a sweeping panorama of the red valley below. Just one tiny dwelling is visible, the packed-earth hogan of Elsie Begay, a 71-year-old Navajo woman. Ms. Begay was featured in a series of articles in The Los Angeles Times in 2006 about serious illnesses that several of her family members developed after living in the area for many years.

The publicity “might have bumped the site up the priority list,” said Jason Musante, who oversaw the $7.5 million cleanup of the mine for the E.P.A.

In trailers and cinder-block dwellings on the Navajo reservation, there is deep cynicism and apprehension about the federal effort. “That’s what they want you to see: something that’s all nice and cleaned up,” said the Navajo manager of a hotel near the Skyline mine. He asked not to be identified, saying that he had already come under government scrutiny for collecting water samples from the San Juan River for uranium testing at a private lab.

For some Navajos, the uranium contamination is all of a piece with their fraught relationship with the federal government.

“They’re making excuses, and they’ve always made excuses,” Ms. Knorr said. “The government should have had a law in place that told these mining companies: you clean up your mess when you leave.”