Comment: Uranium Milling in Tuba City, AZ has left everything around it, in ruins: water, land and air. Please notice both articles on the blog, the lawsuit and the history of the mill! This will be the county's future unless everyone demand the county to ban uranium mining & milling NOW!! Wednesday, May 27, 2009
The Navajo Nation joined a lawsuit against the federal government on Tuesday, hoping to find a party responsible for cleaning up a dump near Tuba City found to be leaching waste into a shallow aquifer.
The tribe is arguing that uranium millers at a mill five miles from Tuba City that was authorized to operate by the Department of Energy pitched milling waste into the unlined dump, and at two or more other locations in the area.
The tribe asserts that drinking water and the health of nearby residents is jeopardized by uranium waste in the dump, and they want all of the contents of the Bureau of Indian Affairs-run dump removed and groundwater pumped for contamination.
The tribes oppose any partial attempts at cleanup.
Congress has appropriated $5 million this year for cleanup at the dump, but that is unlikely to cover all of the projected costs.
The Hopi Tribe filed a notice last week that it intended to sue over the same issue after each of the tribes has been in talks with federal agencies for more than a decade but seen no action.
The lawsuit the Navajo Nation joined was initially filed by El Paso Natural Gas after the company purchased the Rare Metals Corporation and became an owner of a uranium mill near Tuba City.
El Paso was seen by the Navajo and Hopi tribes as a potential party responsible for cleanup, along with the Department of Energy.
So El Paso Natural Gas filed sued against the federal government, hoping to put the responsibility for cleanup on the federal agencies that authorized and regulated Cold War uranium mining.
http://www.azdailysun.com/articles/2009/05/27/news/local/20090527_local_197045.txt
Tuba City Mill Site Coconino County, Arizona
Location: The former Tuba City mill site is located approximately 5 miles east of Tuba City, Coconino County, Arizona, south of U.S. Highway 160 on the Navajo Indian Reservation. It is 85 miles north of Flagstaff, Arizona, and near the Hopi Indian Reservation.
Background: The uranium ores processed at the Tuba City mill came largely from sites in Arizona: the Orphan Lode mine within the Grand Canyon National Park, mines in the Cameron area and adjacent areas, mines in the Monument Valley district, and ores purchased by the U.S. Atomic Energy Commission (AEC) at the Tuba City ore buying station and at other AEC ore buying stations1, including the Globe ore buying station, Gila County, Arizona.2 3
Orphan Lode mine - Uranium mineralization was identified by a U.S. Geological Survey geologist in April 1951 in old copper mine workings at the Orphan mining claim, a lode claim located in 1893 and patented as a copper prospect in 1906. 4 5The mine site is near Grand Canyon Village and about 1,100 feet below the south rim of the Grand Canyon of the Colorado River. Private exploration drilling in 1955 confirmed a high-grade uranium-copper deposit on the claim. The Orphan Lode deposit was in the upper reaches of a vertical, nearly circular, solution-collapse breccia-pipe structure. It is exposed on the canyon wall near the Coconino Sandstone-Hermit Shale (Permian) contact. 6 The pipe structure extends downward from outcrop through sedimentary rocks of Permian and Pennsylvanian ages and bottoms near the middle of the Redwall Limestone (Mississippian age), a vertical distance of about 1,660 feet. 7 The collapse material in the pipe consists of poorly consolidated sand fill, sandstone and claystone breccias with varying calcite cementation, and limey siltstone. 8 9 Uranium ore bodies associated with the pipe occurred as irregular masses in the collapsed material that fills the pipe and in rocks associated with the pipe's peripheral, annular-ring shear zone that defines the border of the pipe. 10 11 Some ore also extended outside the lode claim boundary and onto land belonging to the National Park Service.12 The ore was mined to a depth of about 585 feet, but uranium mineralization associated with the pipe structure is present below that mine level.
Development work at the Orphan Lode mine began in 1953. A three-tower, aerial tramway was completed in March 1955 from the canyon rim to service the mine site. A new 1,800-foot tramway with eight-towers replaced the old one in May 1956. The tramways had limited capability for moving materials to and from the mine. To expand ore production, a 1,590-foot, 2½ compartment mine shaft was sunk on the claim behind the canyon rim from May 1958-January 1959. The shaft was connected to the mine through a 1,200-foot crosscut at the 400 level. Mine development costs at the Orphan were high, as all mined materials had to be transported off site. Cut and fill methods, which involved handling and rehanding waste rock in the underground mine, were used when possible to save on costs for hoisting and surface storage. Mine waste rock could not be stored on National Park Service (NPS) land. Some waste rock excavated during mine-shaft and crosscut construction was used by the NPS for road projects in the park.
The first shipment of Orphan Lode ore went to the AEC's ore buying station at the Tuba City mill in April 1956. Most of the ore mined from the Orphan was hauled to the Tuba City mill for processing. Some ore was shipped in 1958-1960 to mills in Utah and New Mexico, when the Tuba City mill could not take the ore. In 1959 and 1960, some Orphan Lode ore was also shipped to an Ambrosia Lake, New Mexico, alkaline-leach mill that could treat the high-lime ore. 13
Throughout its life the Orphan Lode mine was operated by several owners.14 Cotter Corporation, the last owner, shipped and processed ore from the mine at its Canon City, Colorado, mill from late 1967-early 1969. In April 1969 the Orphan Lode mine was permanently closed due to the high cost of shipping the ore to the Canon City mill. 15
The total Orphan Lode mine ore production (April 1956-April 1969) was 500,432 tons ore containing 4,286,254 pounds U3O8. 16 About 32 percent of the total uranium produced was recovered from ore mined on National Park Service land. The highest grade monthly ore shipment was 726 tons that averaged 2.29 percent U3O8. 17 Some 6.68 million pounds of copper and about 107,000 ounces of silver also were recovered from the Orphan Lode ore .18
Cameron uranium area - Uranium deposits occur in the Cameron area in an area that extends about 30 miles north-south and 12 miles east-west near the town of Cameron, Arizona. 19 The area extends across parts of the Painted Desert and Ward Terrace in the western part of the Navajo Reservation. In the Ward Terrace area east of Cameron, uranium minerals were discovered in 1950 on an outcrop of the Kayenta Formation (Lower Jurassic). 20 From mid 1951 to the spring of 1952, several shipments of uranium ore from small deposits in this area were sent to the AEC ore buying station at Monticello, Utah. In early 1952 ore was also shipped to the AEC buying station at Shiprock, New Mexico. 21
In 1952, uranium was discovered on Chinle Formation (Upper Triassic) outcrops near Cameron by a Navajo prospector who was conducting surface radiometric reconnaissance on behalf of the AEC. 22 Other discoveries were soon made at sites on Chinle outcrops. In 1952, shipments of uranium ore from Cameron deposits were sent to the AEC's ore buying station at Bluewater, New Mexico. 23 By 1954, six operators were shipping ore from several Cameron area mines. 24
In December 1954, the Navajo uranium leases held by the Arrowhead Uranium Company, which had become a major player in the Cameron area, were acquired the Rare Metals Corporation of America.25
The deposits in the Cameron area occurred mainly in the lower 60 feet of the Petrified Forest Member and the upper 30 feet of the underlying Shinarump Member of the Chinle Formation. 26 The ore occurred mainly in poorly consolidated sandstone and in clay-pellet sandstone and conglomerate beds in intraformational channel and scour structures. 27 Ore-grade material occurred in pod- and lens-shaped tabular bodies up to 10-15 feet thick at depressions and bends along ‘channel and scour' trends and was often associated with bentonitic clay. Higher grade ore was associated with carbonaceous trash. 28 Uranium-mineralized fossil logs were mined in some deposits. The deepest open pit mine was 130 feet deep. The average depth for mines in the area ore was about 60 feet. The largest ore body mined contained about 40,000 tons of ore, and the average size for the mined deposits was reported to be about 7,000 tons of ore. The ‘channel and scour' environment accounted for over 95 percent of the ore mined from the Cameron area.
During 1951-1963 about 289,300 tons of ore mined in the Cameron area averaged 0.21 percent U3O8and 0.04 percent V2O5. 29 The ore was classified as ‘low vanadium and low lime.' At depth the ore consisted of uraninite with some sulfide minerals. Ore nearer the surface was oxidized.
In the Cameron area, the deposits generally were of small size, which limited the depth for economical stripping of the ore. Mines were mainly open pits: some underground mining was done via adits driven into pit walls to follow ore trends. The deepest open pit mine was 130 feet deep. The average depth for mines in the area ore was about 60 feet. Four vertical mine shafts were dug to reach deposits. The largest ore body mined contained about 40,000 tons of ore, and the average size for mined deposits was reported to be about 7,000 tons of ore. The small mines depended on the AEC production bonus for profitable operation. 30 At the Riverview mine, uranium ore was mined from down-dropped blocks of sandstone found in a solution-collapse breccia-pipe structure that penetrated the Moenkopi Formation (Upper Triassic). 31
Tuba City ore buying station and uranium mill - In July 1955 Rare Metals Corp. signed a contract with the AEC to produce uranium concentrate at a new mill to be built near Tuba City, Arizona. Construction of the mill began in August 1955. 32 The Tuba City mill operated from June 1956-November 1966. 33
In February 1956, the AEC opened a uranium ore buying station at the mill construction site. 34 Rare Metals leased the mill's ore sampling plant to the AEC pending the mill's completion. The AEC purchased ores at the Tuba City site through June 1957, when Rare Metals began buying the ore. From February 1956 to June 1957, 40,782 tons of uranium ore averaging 0.22 percent U3O8and 0.05 percent V2O5were purchased at the buying station. Rare Metals purchased the AEC's ore stockpiled at Tuba City as well as ore from other AEC ore-buying stations. 35
The original Tuba City mill was designed to process the clayey, low-lime, high-slime, ores obtained from Cameron area mines. 36 After its initial startup period, the mill was rated at 300 tons of ore per day. The milling process for the low-lime ores included ore crushing and grinding, sulfuric-acid leaching, sand-slime separation, and the basket resin-in-pulp ion exchange process for uranium recovery. 37
By the early 1960s, many mines in the Cameron area that had shipped low-lime ores to the Tuba City mill were depleted, and the area’s ore production was in decline. Shipment of Orphan Lode ore to the Tuba City mill began in early 1956. The Orphan ore had higher lime content than Cameron-type ores, and for the mill’s acid-leach process the Orphan ore was blended at the mill with lower lime ores. Cameron area mine production had fallen to only a few hundred tons per year by 1962, and Orphan Lode ore was then set to become the main feed for the mill.38
After an accident closed the Orphan Lode mine in December1961, the Tuba City mill was forced to temporarily suspend operations. At the Orphan mine, hoisted ore was stored in an ore bin attached to the head frame, which was erected over the 2½-compartment mine shaft. The ore bin collapsed in late December 1961 and dumped ore back down the mine shaft. The mine was forced to shut down for several months for repairs. By January 1962, the ore on hand at the mine at the time of the accident was shipped to the Tuba City mill. With Orphan Lode ore temporarily not available and declining ore production in the Cameron area (less than 300 tons of ore in 1962), there was not enough ore feed to keep the mill supplied. In May 1962 the mill closed.39
In July 1962 Rare Metals Corporation was merged into the El Paso Natural Gas Company (EPNG). EPNG signed a new contract in November 1962 with the AEC for the sale of uranium concentrates produced from Orphan Lode ore at the Tuba City mill through December 1966. 40
The need to convert the milling process at the Tuba City mill to handle the higher lime Orphan Lode ore was foreseen as early as 1961, and planning was begun for an alkaline-leach capability at the mill. 41 Addition of the new circuit was completed during the 1962 mill-closure period. Some ‘used' equipment obtained for the conversion was purchased under competitive bidding when the AEC's Monticello, Utah, mill was dismantled. 42 In April 1963, the Tuba City mill was again operational with a new design capacity of 200 tons ore per day. 43
The conversion to alkaline-leach included installation of new ore grinding equipment, a flotation circuit to separate sulfides after grinding, pressure-leach vessels, liquid-solids separation equipment, precipitation tanks, and re-carbonation equipment for leach-solution recycle. 44 Sulfide flotation tailings were sent to the alkaline circuit and the bulk flotation concentrate was processed in an acid-leach circuit. 45 Uranium was recovered from the flotation concentrate by ion exchange. 46
From June 1956-September 1966 the Tuba City mill processed a total of 796,489 tons of uranium ore with an average grade of 0.33 percent U3O8. 47 The mill recovered 4,696,402 pounds U3O8in concentrates, a 90 percent recovery rate. 48 All uranium concentrate produced was delivered under contract to the AEC.
Copper products from the Tuba City mill were shipped to the smelter at Inspiration, Arizona. 49
When the Tuba City mill was closed in September 1966 control of the mill site reverted to the Navajo Nation. Three connected mill-tailings piles containing some 800,000 tons of material and three evaporation ponds remained on the mill site. 50 Earthen dikes protected the tailings510 piles from surface water runoff.
In 1968, under a cooperative program with the U.S. Bureau of Mines, the surface of the tailings piles was treated with a chemical-binder material to prevent the wind transport of fine tailings materials onto the surrounding grazing lands. By 1974, the crust formed on the piles by the binding agent had become damaged, and it was no longer effective.51
A gamma-radiation survey of the Tuba City mill site and adjacent area was made in 1972 by an AEC contractor under an interagency agreement with the U.S. Environmental Protection Agency. Anomalous gamma radioactivity was identified at 14 sites. Seven of these were found to have uranium tailings materials. The contamination was attributed to dispersal of tailings material by wind action rather than by human intervention. Anomalous gamma radiation was found to decrease to background levels at a distance of 0.25 miles from the piles. Along the prevailing wind direction, the gamma radiation decreased to background levels 0.7 miles from the piles. 52
The former Tuba City mill site is situated on a natural terrace about 5,100 feet above sea level. The natural soil cover is unconsolidated sand and gravel overlying the Navajo Sandstone (Lower Jurassic). Natural vegetation is sparse in the area. Southward from the site, the ground surface descends about 400 feet in elevation over a distance of about 1.5 miles towards the Moenkopi Wash drainage. This stream provides some water for livestock and agricultural use. Occasional livestock grazing is the main land use nearby the mill site, and some land nearby is used for dry and irrigation farming. The supply of surface water available from natural precipitation in the area is limited and highly variable. The Navajo Sandstone contains an extensive multiple aquifer system that is an important regional water resource. The aquifer system is vast and encompasses all of the Navajo Sandstone units. 53
UMTRA Surface Remediation: DOE began the surface remediation work at the former Tuba City mill site in 1988 and it was completed by December 1990. Demolition of the remaining buildings and site preparation began in 1986. All of the residual radioactive materials at the mill site, the contaminated windblown materials from surrounding properties, and debris from the demolished buildings were placed in a disposal cell over the existing uranium mill tailings materials and stabilized by compaction. 54
Disposal Cell: The disposal cell covers an area of about 50 acres, is generally triangular in shape, and rises to a height of about 45 feet above the surrounding ground. About 2.3 million tons of contaminated materials with a total activity of 940 curies of 226 Ra are entombed in the cell. 55 The cover encapsulating the disposal cell is an engineered, multiple-layer structure. A low-permeability radon barrier composed of clayey soil was placed directly on the contaminated, radioactive cell contents. The 42-inch thick soil layer is designed to minimize the emission of radon to the air and the downward percolation of water through the cell and potentially into the underlying aquifer. A layer of granular bedding material overlies the radon barrier and is designed to promote the rapid runoff from any precipitation that falls on the cell structure. Two layers of rip-rap material totaling 18 inches in thickness cap the disposal cell to protect it against erosion from wind and storm water. A rock apron surrounds the cell to control runoff water that is shed from the encapsulating cover. On its up-slope sides, the cell is protected by a drainage ditch that collects surface-runoff water and directs it away from the completed cell structure. 56
Responsibility for Remediation: U.S Department of Energy, 100 percent
Stewardship: The U.S. Department of Energy (DOE) is responsible for long-term stewardship at the former Tuba City mill site, including the groundwater cleanup program and the subsequent long-term site monitoring. In 1996, the NRC included the Tuba City Disposal Cell under a general license. Under this license, the DOE has long-term custody, monitoring, and maintenance responsibilities at the remediated site. The DOE maintains data relating to site characterization, design parameters for site restoration, and historical and current site monitoring. The Long-Term Surveillance and Maintenance Program at the DOE's Grand Junction Office will assure the disposal site's safety and integrity.57 The Navajo Nation retains title to the land and tailings.58
Ground Water Program: Groundwater contamination in the Navajo Sandstone aquifer at the Tuba City site resulted from the milling of uranium ores. The water used by the mill to process uranium ore was discharged with the tailings slurry into the original tailings impoundment structures at the Tuba City mill site. The water contained high concentrations of dissolved materials, such as nitrate, sulfate, sodium, calcium, and low amounts of uranium resulting from the ore-milling process. The original tailings impoundment structures were not lined with an impermeable material to prevent the downward percolation of pore water from the pile, and the tailings materials are directly in contact with the natural soil cover. The soil cover is composed mainly of permeable eolian sand that formed on the underlying strata of the Navajo Sandstone.
The contaminated groundwater plume identified by the DOE covers an area of about 320 acres and extends downgradient to the south and southwest from the former mill site. It is estimated that some 3.8 million cubic yards of groundwater are contaminated. 59 Of 18 contaminants identified in the groundwater at the Tuba City mill site, the concentrations for 13 do not exceed the maximum limits established by the U.S. Environmental Protection Agency (EPA) and do not pose a risk to human health or the environment. No remediation for these 13 is planned by the DOE. The groundwater concentrations for four contaminants (molybdenum, nitrate, selenium, and uranium) exceed the respective EPA maximum concentration limits. In addition, the contaminant sulfate is present in the groundwater plume at levels that can cause a potential health risk. The DOE groundwater remediation strategy includes active remediation to reduce the concentrations of these five contaminants in the groundwater plume. 60
The DOE designed program for clean-up of the Navajo Sandstone aquifer at the former Tuba City mill site includes the extraction of contaminated groundwater from the plume and removal of the contaminants by distillation. About 90 percent of the treated groundwater will be returned to the aquifer via injection wells and infiltration ditches. The extraction of contaminated water from the aquifer and re-injection of clean water will contain the further spreading of the five contaminants. A monitoring program will continue throughout the groundwater cleanup phase to assure that the aquifer restoration standards established for the project are met. 61
TO SEE FOOTNOTES: http://www.eia.doe.gov/cneaf/nuclear/page/umtra/tubacity_title1.html
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