The Future of U.S. Nuclear Power Could Rely on Wyoming

 The Future of U.S. Nuclear Power Could Rely on Wyoming

Can the Uranium Province of Wyoming Compete with the Athabasca in Canada or the Northern Territories in Australia?

One of the top geologists in Wyoming, Ray E. Harris, who has been working for the Wyoming Geological Survey since 1982, joked, "Geology is 90 percent terminology and 10 percent science." On March 7th, he passed away. Mr. Harris was interviewed and met with two weeks ago. His office was right next to the University of Wyoming in Laramie, so everyone we met in Wyoming who was into uranium mining had been there at some point.

Researching and researching uranium deposits was Ray Harris's life's work. In addition to his involvement in uranium discovery, development, and mining, he had an extensive understanding of the geology of every major uranium deposit on the planet. "The genesis of uranium deposits in Athabasca, Canada and Northern Australia - Wyoming exploration significance.", written by Ray Harris and published in 1986 in a Geological Survey of Wyoming Public Information Circular, was an original and potentially contentious concept. Harris stated in his introduction:

"There are uranium occurrences in Wyoming that are comparable to those in Australia and the Athabasca Basin, and it seems like there could be a uranium deposit of comparable size in Wyoming as well."

One third to one quarter of the noncommunist world's proven reserves are located in these two locations, which amount to 436,360,000 tons of U3O8, as Harris admitted in his report. Meanwhile, in 1982, the United States had 203,000 tons of uranium reserves, valued at $30/pound. At 32,700 tons, Wyoming had a portion of the total mineable material. He made a daring claim, but he was game for discussion rather than flat rejection.

Maybe what Harris says is true. E.S. Cheney wrote an essay titled "The Hunt for Giant Uranium Deposits" in American Scientist in 1981. In it, he indicated that a giant deposit would include around 100 million pounds of recoverable U3O8. Will there be more than one massive uranium deposit from the pieces? The Wyoming Uranium Province is comprised of various uranium districts, including Gas Hills, Shirley Basin, Crooks Gap, Red Desert, Powder River Basin, and Black Hills. Within each district, there are a few to numerous individual uranium deposits, as stated by William Boberg in his 1981 article "Some Speculations on the Development of Central Wyoming as a Uranium Province" published in the Wyoming Geological Association Guidebook. Part 2 of this Wyoming Series features Senator Robert Peck, who is well-versed in uranium, who predicted that the Gas Hills had "50 to 60 million pounds of recoverable uranium proven by previous drilling."

In his paper titled "Uranium Provinces of North America - Their Definition, Distribution and Models," Warren Finch stated that "... provinces are identified by the distribution of major uranium clusters, generally of a size of 500 tons and more U3O8..." This was published in U.S. Geological Survey Bulletin #2141 (1996, US Government Printing Office, Washington). Geologists have been eager to compare similar geological settings between geographically diverse uranium deposits since January 1970, when S.H.U. Bowie presented a paper to the International Atomic Energy Agency in Vienna outlining the process of defining uranium provinces and searching for major deposits. The goal was to more accurately define uranium provinces.

"There are no producing ore bodies in the United States similar to those of the Athabasca Basin and Northern Australia," Ray Harris said in the article cited earlier. However, he did mention that two deposits that are not being mined could have a similar origin. The deposits in question can be found in the areas of Copper Mountain in Fremont County, Wyoming, and Chatham in Pittsylvania County, Virginia. Editor's Note: The Copper Mountain property owned by Strathmore Minerals, which was drilled from 1997 to 1998 by Anaconda Uranium Corp., has a historical contained resource of about 38 million pounds of U3O8, as stated on the company's website. This resource estimate cannot be confirmed by Strathmore due to their lack of work.

According to Harris, it would be premature to rule out the possibility of a high-grade uranium deposit in the US that shares geological similarities with a deposit in the Athabasca Basin. He mentioned a uranium discovery in Chatham, Virginia, that measured four pounds of uranium oxide per ton of ore and might potentially hold thirty million pounds of the element. His description of the location was reminiscent of non-conformity uranium deposits: The formation of this deposit appears to be comparable to that of the Athabasca and Northern Australian deposits at first sight. A temporary setback for this deposit has occurred as a result of the uranium mining moratorium that was passed by the Virginia Assembly. However, in the first installment of this series, the governor of mining-friendly Wyoming is pressured by firms to attract uranium projects and investment to his state.

The Potential of Wyoming's Geology for U.S. Utilities

It is well-documented that Wyoming's sandstones include numerous roll-front uranium deposits. Wyoming is the U.S. hub for in situ leach mining (ISL), sometimes called solution mining. This is due to the state's mining-friendly policies, the abundance of roll-front uranium deposits, and the rising spot uranium price in the uranium bull market. On the other hand, there might be a bigger uranium deposit, one that might compete with the Athabasca Basin or perhaps Northern Australia, as Ray Harris had hinted at during our interview. The aforementioned studies from the 1980s and Harris' 1993 paper titled "Geological classification and origin of radioactive mineralization in Wyoming" both argue for the same premise.

There should be a uranium deposit associated to nonconformities someplace in Wyoming, according to Harris's 1986 paper, "Given the impressive length of exposure, the relatively shallow subcrop depths of favorable nonconformities in Wyoming, and the great amounts of uranium available for mobilization." The Copper Mountain area of Fremont County is one possible location, as Harris mentioned. Under the Copper Mountain region, "Uranium occurs in fractured and faulted Precambrian rocks and in the nonconformably overlying Eocene Tepee Trail Formation," according to Harris's writings. Although the uranium occurrence is not economically viable, its size and quality are encouraging. In addition, he mentioned that the uranium is connected to faults and fractures that are part of the Laramide North Canning fault system. An extensive drilling campaign was carried out by Rocky Mountain Energy Company at the North Canning deposit.

The Precambrian granite and contained metasediments are where mineralization takes place, according to Harris. Reportedly, low-temperature pitchblende and coffinite make up the bulk of the mineralization. North Canning deposit and uranium deposits related to nonconformities were compared by Harris. His reasoning was that the deposit probably produced by mechanisms that were comparable to those in the Athabasca and Northern Australian regions. We contacted David Miller of Strathmore Minerals (TSX: STM; Other OTC: STHJF) to inquire about their holdings in Copper Mountain. “We own all the federal minerals in the area that covered uranium mineralization—about 75 percent of the gross uranium resources,” he said via email. About 60% of the Canning Deposit is owned by us and 40% by Neutron. About a hundred mining claims are located in the region owned by Strathmore Minerals.

There is still much uncertainty about where the uranium in Wyoming's roll-front deposits came from. "The major deposits of Wyoming occur in the Lower Cretaceous Inyan Kara Group of the Black Hills, in the Paleocene Fort Union Formation in the Powder River Basin, in correlative Eocene sandstones in all of the major uranium districts," described William Boberg in 1981. "The predominant type of uranium deposit is the roll-front sandstone deposit in Tertiary continental fluvial basis developed between uplifts," Warren Finch wrote later on about the roll-fronts in Wyoming, quoting from his earlier work. These mineral resources were created when groundwaters rich in uranium, which had seeped into the host sandstone from the basin margins, underwent oxidation. Uraniferous Precambrian granite, which supplied the host sandstone with sediment, and underlying Oligocene volcanic ash sediments were two potential uranium sources. Ray Harris seemed to be more of a traditionalist. The second theory about the origin of uranium has received more support from William Boberg.

Boberg stated, "In a geologically short period of mineralization, large altered tongues and discrete deposits were formed when a unique, uranium-rich, ore-forming liquid invaded very porous and permeable young sediments." This liquid apparently originated from Precambrian granites and volcanic ash falls. An average altered "tongue" might take 700,000 years to form, whereas an average roll-front uranium deposit could take more than 50,000 years.

The deposits were thought to have been created by the massive and numerous uranium-enriched ash falls that occurred during the Middle Eocene volcanic eruptions, according to Boberg. He stated, "The most important thing is that over the course of forty million years, ash from a number of different extrusive centers began to fall over Wyoming and the neighboring states," referring to a string of volcanic eruptions that started around fifty million years ago.

His analysis of the volcanic ash yields important information about the formation of the uranium deposits in Wyoming:

A distinctive fluid, acidic and ionized, was created as the first rains flushed the volcanic ash. The pH was nearly neutralized when this fluid's buffering reacted chemically with the Precambrian granites, ash, and other rocks, but more uranium was leached from the granites and likely the ash. The unique oxidizing fluid, which was enriched with uranium, was formed by the constant supply of dissolved oxygen made possible by the climate and heavy rainfall. This fluid then penetrated the unconsolidated, reduced sediments, oxidizing them and carrying the uranium to its ultimate state of maximum oxidation.

According to Boberg, the roll-fronts formed because fluids moved quickly through the porous sediments, which meant that large oxidized tongues could form with the younger sediment and that scattered uranium deposits could form at the redox (oxidized reduction) interface within a million years. Because they are so close to the granite and ash sources, deposits formed around the granitic highlands tend to be larger and of higher average grade.

An example of a near-surface roll-front redox deposit was the uranium found in Tertiary sandstones by J.D. Love in 1951. A roll-front deposit typically has a C-shaped or otherwise sinuous linear trend. By the early 1940s, the cross-sectional arrangement had been dubbed a "roll" by miners in Utah and Colorado. Sandstones with roll-fronts are often encircled by less porous shales on either side. Sandstone, both changed and unaffected, forms a barrier around the "rolls" in Wyoming. In the absence of changes, it takes on a convex shape, and vice versa when entering altered ground. Uranium concentrations "decline gradually away from the convex boundary in reduced rock, and concentrations abruptly decrease away from the concave boundary" in Harris's modeled roll-front uranium deposit.

Along a roll front, uranium is not always present everywhere. The distribution of additional elements, like vanadium, selenium, molybdenum, copper, silver, lead, and zinc, can make it unequal. Geologists search for uranium ore by looking for places where coarse-grained sandstones transition into finer-grained or clay-bearing counterparts. It is possible to mine uranium from roll-front deposits, according to uranium geologists, provided the deposit is below groundwater. Elevation of deposits above the water table allows for the erosion and modification of uranium concentrations.

While Harris was intrigued in uranium, it was not the roll-front deposits but rather the tabular redox occurrences that can be found across Wyoming. Specifically, he discovered them in the Black Hills' Cretaceous Inyan Kara Group. A uranium mine in New Mexico, as with many others on the Colorado Plateau, is a tabular deposit, as Harris put it. While roll-front mineralization cuts across bedding, the tabular bodies, as pointed out by Harris, are characterized by their irregular tabular shape and are located parallel to the bedding. According to Harris, "the limbs and detached limbs of roll fronts left in less permeable rocks at fluvial channel margins" were among the tabular bodies found in Tertiary rocks. Additionally, he mentioned that oxidized rock, which contains large quantities of other rocks like coal or pyrite, could potentially maintain tabular bodies.

No matter how you slice it, uranium occurs in almost all of Wyoming's major time divisions, therefore Harris agrees with other geologists that the state is a uranium province. "Uranium was available for mobilization during every major weathering period related to the nonconformities," he said in his conclusion. While we were on our last legs, he persuaded me that a lot of uranium development companies should put more money into exploration to locate the elephant uranium reserves he had mentioned in three separate places. The straightforward ISL extraction of uranium from already drilled sites didn't seem as fascinating to him as that. Those regions, like others we spoke with, won't have much in the way of surprises, but they will provide the consistent, lucrative uranium extraction that fosters the growth of startups. Utilities in the United States and elsewhere are currently vying for that. More and more businesses are starting ISL uranium operations, which means Wyoming uranium might power a lot of nuclear reactors in the US.

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