Just when we thought it was the end of the coal era, the discovery of rare earth mineral deposits could mean that coal mines still have a role to play in the future of the energy sector. There have been proposals for the transformation of coal mines into geothermal facilities and other renewable energy sites, but this discovery could give coal mines a new lease of life for the more conventional purpose of mining.
There has been a significant global push to move away from coal mining in favor of less dirty fossil fuels and renewable alternatives. Once considered the driver of the industrial revolution, coal is now viewed by many as an unnecessary evil. Simultaneously, the demand for metals and minerals associated with renewable energy production and clean technologies is increasing, making mining for other elements critical. There are seventeen metallic elements, known as rare earth elements (REE), many of which are essential for the manufacturing of everyday technological devices and green energy components, such as batteries and semiconductors. In 1993, 38 percent of the global production of REEs was in China, 33 percent was in the United States, 12 percent in Australia, and 5 percent was in Malaysia and India.
This year in May, the U.S. firm Ramaco Resources, researchers from mining consultancy Weir International, and the U.S. Department of Energy’s (DoE) National Energy Technology Laboratory (NETL) published a paper including a technical assessment of REE. In the report it revealed that these minerals were present at a coal mine in Wyoming, suggesting they may be present in other coal sites. Ramaco stated, “Following eighteen 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 United States.”
The discovery came about when Ramaco decided it was no longer worth developing the site as a thermal coal mine due to global changes in the perception of coal since it purchased the location around a decade ago. The company was questioning how it may develop the site using an alternative approach, and the discovery of REE has given the spot great potential for development.
At present, China dominates the global production of rare earths, producing around 90 percent of the world’s REEs. Ramaco’s mine could, therefore, provide North America with a strategic advantage for regional production. Most REE deposits outside of China are found in igneous hard rock deposits and are hard to extract, making the Wyoming coal mine look ever more appealing. Ramaco stated, “In contrast, the REEs from the Brook Mine are characterized as “unconventional” because they are largely found in clay strata located above and below the coal seams themselves.” Further, “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,” the company added.
The DoE is searching for REE in other parts of the U.S. as it looks to develop its regional energy supply chains. In April, it provided West Virginia University with a grant of $8 million to explore coal and rare earth extraction. The DoE is hoping to develop innovative methods of extraction to enhance using a “pioneering method to extract and separate rare earth elements and critical minerals from acid mine drainage and coal waste.” Similar research is also taking place at Penn State.
It’s not just the U.S. that is exploring the potential for REE deposits in coal mines as researchers in South Africa are also assessing the possibility of mineral extraction. The Clean Coal Technology research group at the University of Witwatersrand, Johannesburg published a paper earlier this year that discussed the chemical composition of coal. The group found that the REE content in the coal being analysed was over 225 parts per million, a concentration higher than the cut-off grade of 130ppm needed to extract rare earths in coal. This means that the coal can be reprocessed as raw materials to be used to support renewable energy production and clean technologies. This is just one of several areas of exploration by governments and researchers to find innovative ways to access critical metals and minerals for clean energy production.
The global demand for REEs is expected to rise by around 600 percent by 2040, and it is not yet clear how governments will meet this demand. While extraction from coal shows some potential, the question of environmental impact lingers, particularly as countries worldwide strive to meet net-zero carbon emissions pledges. Sweden, South Africa, and Australia have all shown interest in REE extraction from coal, while the U.S. and Europe are attempting to develop regional supply chains and reduce their dependence on China.
There could be great potential for the use of coal sites to extract rare earth elements from coal, as producers look for alternative uses for the fossil fuel. As countries shift away from fossil fuels to renewable alternatives, the demand for REEs will continue to increase and governments must meet this demand if they want the global green transition to be a success. However, there is still great uncertainty over the potential impact of this type of extraction on the environment, which will need to be fully assessed before coal mines are developed for this purpose.
By Felicity Bradstock for Oilprice.com
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