In association with researchers from the Department of Energy’s National Energy Technology Laboratory (NETL) and analysts at mining consultancy Weir International, metallurgical coal producer Ramaco Resources Inc. have released an independent Exploration Target report with technical assessment of rare earth elements (REE) found at its Brook Mine in Wyoming.
Following 18 months of extensive core drilling and independent chemical analysis, NETL researchers and Ramaco now believe that the Brook Mine property contains perhaps the largest unconventional deposit of REEs discovered in the US.
In particular, the mine ranks among the highest relative concentrations yet discovered of magnetic REEs (MREE) such as heavy REEs Terbium and Dysprosium, as well as lighter REEs such as Neodymium and Praseodymium. Initial estimates are that approximately 28% of deposit concentrations may be in the form of MREEs.
NETL analysis shows that core samples from the Brook Mine represent highly promising, world-class MREE and HREE accumulations. These deposits contain these valuable REEs on par with conventional REE deposits, but with much less of the low-value lanthanum and cerium that must be removed by separations. Based on this data, the Brook Mine could rank among the more promising deposits on a worldwide basis, including Chinese HREE deposits.
There is currently only one active mine for magnetic REEs in the United States, located near the Mojave Desert in California. Magnetic REE materials are used in electric vehicle motors, advanced military technology, medical devices, and much more.
The Brook Mine comprises over 15 800 acres outside of Sheridan, Wyoming, one of the largest privately controlled mineral reserves in the Western United States. Roughly 4500 acres were permitted for mining in 2020, which is where the initial assessment programme has been conducted. Mining at the Brook Mine could begin as early as 4Q23, following additional mining development and assessment. The additional 11 300 acres will be also assessed and could provide opportunity to increase the scale of the overall development in the future.
China currently produces the vast majority of REEs, which are increasingly important in defence, industrial, and consumer technologies. Congress and the Department of Energy have earmarked billions of dollars toward this goal, and a bipartisan bill introduced earlier this year would establish tax credits to support the production of magnetic REEs like those found at the Brook Mine.
The majority of REE deposits outside of China are associated with ‘conventional’ mines and found in igneous hard rock deposits, which makes them both difficult and expensive to mine and process. In contrast, the REEs from the Brook Mine are characterised as ‘unconventional’ because they are largely found in clay strata located above and below the coal seams themselves. It is expected they can be mined using normal surface mining techniques and processed in a more economic and environmental manner than conventional REE mines.
A report from Weir International stated: “The coal seams can contain significant quantity of REEs, making the coal seams an attractive source for these valuable minerals on an ash-basis. The REEs are believed to have been incorporated into the coal during its formation and are found in association with clay minerals and organic matter in the coal seams. Interburden between the coal seams also contain elevated levels of REEs, primarily in clays, carbonaceous clays and siltstones and not necessarily associated to the coal seams.… Ramaco’s sample collection, preparation, security, and testing protocols are well documented and suffice to provide consistent, reliable, and verifiable data.”
Ramaco plans to analyse the appropriate mining, processing and mineral development plan for the REEs, along with a comprehensive economic analysis. Ramaco’s Board of Directors has authorised continued assessment of this opportunity, and additional testing results will be released periodically.
Ramaco CEO and Chairman, Randall Atkins, said: “We view this as an exciting and perhaps transformative new direction for our company. We will approach the potential to develop critical minerals with the same conservative capital expenditure and development discipline that we have applied to our core metallurgical coal business. We are also well positioned to allocate initial capital to begin a step-by-step development programme.
Atkins continued: “We of course recognise that any new mine project, especially one involving emerging technology, is fraught with uncertainty. There is much work to do, before we can determine the commercial feasibility of REE extraction at the Brook Mine. But we will evaluate the overall business proposition of developing these REE critical minerals to their highest value proposition to Ramaco, and frankly also to the country. If additional diligence continues to confirm the opportunity, then Ramaco can expand its national footprint into becoming both a low-cost supplier of strategic REE critical materials from Wyoming, as well as continuing as a producer of metallurgical coal in Central Appalachia. We will supply periodic updates as this REE project unfolds.”
- Weir estimates a range of between 181 000 and 226 000 t of magnetic rare earth oxide (REO) at the Brook Mine site.
- A total of 131 core holes targeting the REE mineralisation have been drilled to date, with 58 of the core holes having been scanned using x-ray fluorescence. An analysis of 965 test samples have been conducted using inductively coupled plasma (ICP) spectroscopy of the elemental composition of different cores, which tests form the basis of analysis by Weir International.
- The results from ICP scan observations show an average of 28% overall concentration of both the four primary magnetic REEs as well as other magnetic concentrations.
- The current exploration target encompasses a range between roughly 636 000 and 795 000 in place t of 100% total rare earth oxide (TREO) with all concentration grades. Core drilling and chemical test analysis will continue on an ongoing basis to further delineate the deposit.
- The Brook Mine samples plot in the highest quartile relative to other REE ore bodies worldwide, with promisivity of the Brook Mine REE deposits falling along the promising to highly promising spectrum for the full range of REEs, including the four highly valued REEs with magnetic properties.