Rare earth mineral deposit, Brook Mine, near Sheridan, WY

[Astronuc]

Randall Atkins, the chairman and CEO of coal producer Ramaco Resources, which mainly operates in Virginia and West Virginia, bought the unassuming Brook Mine in Wyoming 12 years ago. Apparently, it may offer a potentially colossal investment return after discovering “rare earth elements” worth $37bn at his reserve.

https://www.independent.co.uk/news/world/americas/wyoming-coal-mine-rare-earths-b2445248.html

Brook Mine’s jackpot, which includes neodymium, praseodymium, dysprosium and terbium, according to the company, should not be underestimated in its uses.
. . .

If the analysis of the elements is positive, this would be the first new rare-earths mine in the US since 1952, the Wall Street Journal reported.

Currently, the coal company was only permitted to mine on 4,500 acres of the 15,800 acres the site stretches across, but they said in the release they hope to expand their search.

The Wall Street Journal has a similar article.

 

[Baluncore]

I am very suspicious of news articles like that.
There is no estimate of the extraction cost of “rare earth elements” worth $37bn.
I would watch to see if the share price bubbled, then sell half my stock at the silly high price.

 

[Vanadium 50]

For a prospectus, please send a SASE to Sam Bankman-Fried, Leavenworth, Kansas,

OK, that's a bit unfair, but we're still in the hype phase. We don't know how much is actually there, nor how much such a find will depress the market ($37B is four years worth), nor which rare earths are present (some are more useful than others) nor what the Chinese reaction will be - which could also be disruptive.

 

[Astronuc]

I was more interested in the geological aspects of the minerals/elements. Rare earth minerals can form due to successive neutron absorption by nuclei with beta decay, as well as by fission of U and TU elements. The business case will work itself out, and investors, or prospective investors, should do due diligence and independent analyses/assays.

 

[Baluncore]

I was more interested in the geological aspects of the minerals/elements.

What is the relationship between the coal mining and the rare earth minerals? I guess to become a good mine for pure carbon, the coal is old, has lost its volatiles, and the organics have been reduced to carbon.

Is the source of rare earths from bioaccumulation, like germanium, or an unrelated formation, deeper in, or below, the stratigraphic section?
Is there a reference link to the geological interpretation of the rare earth mineral concentration?

 

[Vanadium 50]

I think they just have a hole in the ground and a convenient way to get things out of it.

Rare earth geochemistry is complex, as different sources have different mixes of the various elements. Also, rare earths aren't terribly rare - there's about as much cerium as copper.

 

[Astronuc]

What is the relationship between the coal mining and the rare earth minerals? I guess to become a good mine for pure carbon, the coal is old, has lost its volatiles, and the organics have been reduced to carbon.

I think it has to with the source of carbon (sea life, as in animals and flora, or marsh plants, or forests, which then get covered by sediment and/or lava flow. The coal in the Appalachian Mountains is different from coal from the Rockies, e.g., Powder River Basin in Wyoming. Rare earth minerals have been found in coal ash, and there has been some thought about extracting such minerals from coal ash.

Coal seams in West Virginia were deposited 320 - 286 million years ago, in a physiographic setting that was a complex of vast coastal swamplands barely rising above sea level. Layer by layer fans of sediments were deposited here by rivers sourced from the east from highlands now long gone. These coastal swamps and river deltas sank ever deeper, as layers of sand and mud were deposited, along with occasional coal beds-- piling up many thousands of feet of sediments which grew hotter as they sank deeper. Coal seams can be used as a sort of thermometer, indicating by their coal rank the deepest depths to which they and the rock layers that surround them have been buried.

The earth exerts an average geothermal gradient of about 1.5° F for every 100 feet of burial depth. As coal seams are depressed ever-deeper into the earth under accumulating sediments, much of the water and volatile matter are driven away, leaving behind the fixed carbon as well as residual amounts of ash, sulfur, and tiny amounts of a few assorted trace elements. The extent of this de-volatilization varies according to the deepest depth of ultimate burial, resulting in a continuous series of coal grades, ranked according to the relative percentages of fixed carbon they contain.

https://geocraft.com/WVFossils/coal_rank.html

I suspect that applies to eastern Kentucky, Virginia, Pennsylvania, and Ohio. I know that Anthracite mining in Pennsylvania was substantial back in the day, and now the Marcellus shale provides natural gas (methane).

The Appalachian mountains have uranium and thorium deposits, as do the Rocky Mountains, in spots. Decay products, e.g., radon, are found in these areas. Lanthanides are also found in the same general area, but not necessarily co-located.

Distribution and occurrence of rare earths in the thorium veins on Hall Mountain, Idaho​

https://pubs.usgs.gov/publication/70156511

https://pubs.usgs.gov/periodicals/mcs2023/mcs2023-rare-earths.pdf

https://pubs.usgs.gov/publication/cir1454

Rare Earth Element Mineral Deposits in the United States (2019)​

https://pubs.usgs.gov/circ/1454/circ1454.pdf
Over millions of years, with erosion of mountains from rains, wind and glaciation, it's possible some deposits have been dispersed from their origin. Geochemistry is complex, and it has likely changed considerably over the millions/billions of years. It is a matter of finding favorable deposits for exploitation.

What is unique about the deposit/geology just northwest of Sheridan (just off I-90, Exit 14), or rather near the unincorporated community of Monarch, WY?

 

[Vanadium 50]

The coal in the Appalachian Mountains is different from coal from the Rockies,

Says Phoebe Snow
About to go
Upon a trip to Buffalo
"My gown stays white
from morn till night
Upon the Road of Anthracite"

@jtbell may want to comment.

I don't think terrestrial rare earths are fission products, at least not terrestrial fission. There is 20x as much cerium as uranium - the earth isn't that old. Heck, there's 5x as much cerium as lead.

They tend to be expensive because they are relatively difficult to separate from one another - not because they are intrinsically rare. I got a quote for gadolinium oxide at $9/lb in bulk.

 

[Baluncore]

I found Ramaco Carbon, Brook Mine, at "Cleanburn", Wyoming. Google Earth 44.90°,-107.02°
The name says it all.

 

[diogenesNY]

There has been a revived interest in rare earths in the US over the last decade and there are any number of rare earth mining companies. For various reasons, primarily economic, none of those companies are actively mining. One of them is processing ore that was previously mined and has just lain in a pile for decades. The company in question is MP Materials. [ https://mpmaterials.com/ https://en.wikipedia.org/wiki/MP_Materials ]

Saying that it would be the first new rare earth mine (in whatever period) is kind of like saying Blimpco will be the first modern Airship company in decades as soon as they secure financing, design and then build a blimp.

Those reserve numbers are largely non-meaningful. there are many billions if not trillions worth of rare earths that are documented or at least estimated, but mining, extraction, processing and remediation costs are not accounted for. In many scenarios, much of those minerals would not be economically viable to be mined even imagining sci-fi level mining and processing techniques. Concentrations and what sort of mineral deposits in which they are embedded are also a major question.

USGS has lots of documented rare earth deposits. Much of it on claimable/leasable BLM land.

It is worth noting that lumping all RE elements together as a minable resource is a bit misleading too. Usually they are divided into lights and heavies, and values vary dramatically for what each is worth. Cerium is pretty cheap and is used extensively in industrial abrasives. Neodymium is used in high power magnets and is in increasing demand. Some of the rarer heavies are critical for advanced 'smart' weapons, and the only current commercial source is China.... (edit: not strictly true: there are some other non-us sources including Australia and IIRC Russia and some eastern Europe and elsewhere, but China dominates, and the Australian rare earths, and even the US pre-mined ore is being sent to China for processing) This is one reason for the increased interest in the last decade. (The China rare earth economic development story is really interesting, however a bit outside the scope of PF).

Notable also is the fact that major top tier government labs and high level academic institutions are actively researching new methods of processing rare earths and have had significant publications... off the top of my head MIT had a major paper in the journal Nature in the last year. (I can dig up a citation if desired). Developing cost effective processing techniques is really the big race at the moment. Most of the non-mining rare earth companies that have mines are putting most of their resources into developing and marketing rare earth processing, as opposed to actual extraction of ore from the ground. Ucore is a good example of this. [ https://ucore.com/ ]

It is a big area of future interest and development, and arguably an economic imperative for future tech production in the US, but the hype is still drowning out a lot of the (not insignificant) reality.

Beware of FOMO.

 

[DrDu]

Rare earth minerals can form due to successive neutron absorption by nuclei with beta decay, as well as by fission of U and TU elements.

I think that in at least 99.9% of the cases, rare earth minerals (as opposed to the elements) don't form due to these processes. Most rare earth elements on earth were formed before earth like most other elements. The minerals we are mining today mostly formed in the phanerozoic. Lanthanides, as well as Uranium, Thorium, Boron or Fluor are incompatible elements, i.e. during magma differenciation, they remain in the melt until the very end and therefore often show up together in Carbonatitic rocks (e.g. the Bayan Obu deposit in China) or pegmatites like the Tin Mountain deposit in the US.

 

[Astronuc]

I think that in at least 99.9% of the cases, rare earth minerals (as opposed to the elements) don't form due to these processes. Most rare earth elements on earth were formed before earth like most other elements.

I was referring to the formation of heavy elements (lanthanides and actinides) during the R or S process, which ostensibly occurred in some kind of supernova before the formation of the earth. At some point, they were captured by the earth, or proto-earth. Wherever there are neutrons and actinides, especially TU elements, there is the possibility of fast (neutron) fission, and where there are intense magnetic fields and production of high energy gammas (E > 8 MeV), there is the potential for photo-nuclear reactions, e.g.,. photoneutron, and the case of U and TU elements, photofission.

Sometimes the lanthanides are found in formations with actindies (main U, Th, and decay products). But apparently there are some formations of carbonatites that have little or no actinide co-deposits.

Rare earth elements are found in some uranium ore deposits.
https://www.sciencedirect.com/science/article/abs/pii/S088329271730313X

There appears to be a cleaner source of rare earth ores in Montana along the Idaho border.
https://northamericanmining.com/ind...rade-rare-earth-deposit-uncovered-in-montana/

I was reading an article that indicated that Molycorp (operators of the Mountain Pass Mine in California) had found radioactive ores along with the rare earth element ores. In the case of Mountain Pass, sludge from evaporation ponds containing uranium and thorium was of sufficient concentration that the corporation had sought permits to ship it to Utah for milling. Without that processing, they had a costly waste problem. Molycorp eventually declared bankruptcy, and now another entity MP Materials runs the operation (since about 2017) at Mountain Pass.
https://mpmaterials.com/what-we-do/#our-facility
https://www.geologyforinvestors.com/mountain-pass-americas-once-and-future-rare-earth-king/

I have also read that deposits like that at Mountain Pass are very high in the over-produced light REEs like lanthanum and cerium, which results in low prices, and short on heavier REEs like Tb, Dy, Ho, . . .

https://pubs.usgs.gov/publication/70138176

Besides the original formation of the REE in stellar nucleosynthesis, the geochemistry and subsequent concentrations in certain locations is also very interesting.

https://www.science.org/doi/10.1126/sciadv.abb6570
https://www.nature.com/articles/srep10231

 

[Astronuc]

The Halleck Creek mine project in Wyoming claims "4.73 million tonnes of contained Total Rare Earth Oxides (TREO) including Neodymium (Nd) and Praseodymium (Pr) oxides," with "Exceptionally low levels of radioactive penalty elements Uranium and Thorium further reducing costs while boosting the ESG profile."

https://americanrareearths.com.au/projects/halleck-creek-wy/

https://www.wyomingpublicmedia.org/...d-mean-a-new-mining-rush-in-the-mountain-west

The Halleck Creek mine project is about 20-25 miles from Laramie, or about 30 miles from Cheyenne, and about 250 miles SSE of the Brook mine near Sheridan/Kleenburn, WY, which is up near the border with Montana.

So, if all the projects produced at the same time, they'd depress prices for the elements, since there would likely be an over supply, unless demand picks up for whatever markets use the light REEs.

 

[Astronuc]

Back to the Brook Mine project. From Ramaco Resources:
https://ramacoresources.com/critical-minerals-rees/

The REE Exploration Target is located within Ramaco’s mineral holdings at its planned Brook
Mine Property located approximately seven miles north of Sheridan, Wyoming in Sheridan
County. The Burlington Northern Railroad and Interstate 90 are located along the southern
boundary of the current Brook Mine permit area.

The Brook Mine Property is situated in the Sheridan Coal Field in the northwestern portion of the
Powder River Basin (PRB) coal producing region of the of the United States (see Figure 1.1-1).
The United States Geological Survey (USGS) 7.5-minute quadrangle maps are Acme, Hultz
Draw, Monarch, and Sheridan.

The Brook Mine Property consists of approximately 15,800 acres of Ramaco owned and leased
mineral holdings located in Sheridan County, Wyoming. Ramaco acquired the Brook Mine
Property in 2011 from the Sheridan-Wyoming Coal Company. When Ramaco began
development of the Brook Mine Property as a thermal coal resource in 2012, Ramaco originally
permitted approximately 4,600 acres that it regarded as the optimal area for a new surface coal
mine. As Ramaco began further core drilling exploration in 2021 and 2022 relative to REE
exploration, Ramaco decided to continue to drill in areas within the original permit boundary
in order to leverage the existing drilling core available for sampling.

As such, the REE Exploration Target is limited to the current permit boundary of the Brook
Mine Property. Ramaco has indicated its intention to proceed with additional drilling and
assessment of additional areas of the Brook Mine Property to assess the potential for expanding
its REE Exploration Target beyond the current permit boundary.

From Weir International Technical Report for Ramaco Resources
https://ramacoresources.com/wp-cont...ernational-Brook-Mine-Assessment-05.03.23.pdf