Historic mining for future battery metals
PA mines offer win-win-win cobalt and manganese source Metal Tech News - December 22, 2021
Last updated 12/28/2021 at 2:04pm
Pennsylvanian coal helped to fuel America's Industrial Revolution, and mines in the Keystone State have since provided a domestic source of iron ore, cobalt, nickel, and various other metals. Now, researchers at Pennsylvania State University have identified a potential motherlode of battery metals to feed into America's EV Revolution in waste left behind by more than two centuries of mining in the commonwealth.
"Preliminary estimates indicate that waste left by coal mining activities in Pennsylvania contain tens of thousands of metric tons of cobalt and hundreds of thousands of metric tons of manganese," said Pete Rozelle, lead author of a report on battery metals in Pennsylvania mine waste and adviser on mineral resources to Penn State's College of Earth and Mineral Sciences. "One metallurgical waste deposit in the commonwealth may contain a half-million metric tons of manganese."
This could offer a much-needed domestic supply of two of the metals critical to lithium-ion batteries for which the U.S. is heavily dependent on exports and is expected to be in short supply due to the electric vehicle sales targets set by the White House and American automakers.
"Cobalt and manganese are two battery metals that are crucial to battery performance, longevity, and energy density in the lithium-ion batteries that power electric vehicles," said Sarma Pisupati, professor of energy and mineral engineering and director of Center for Critical Minerals at Penn State. "Almost all production of raw materials for lithium-ion batteries, apart from some lithium extraction and refinement, occurs abroad today."
Finding a means of producing these battery metals from historical Pennsylvania mines has the potential to offer a win-win-win scenario for the commonwealth and nation – new economic opportunities for the commonwealth impacted by the waning of coal markets as the U.S. rapidly transitions to low-carbon energy and transportation; a domestic source of two of metals that go into the lithium-ion batteries that power electric vehicles and renewable energy; and a means of paying for the restoration of legacy mining sites that date back to the 18th century.
"The recovery and sale of cobalt and manganese from these materials can provide economic opportunities in distressed areas of Pennsylvania and revenues, when integrated with the reclamation of mines and industrial sites hosting the materials, to help cover reclamation costs," said Rozelle.
The Penn State researchers examined two categories of byproducts left behind by legacy Pennsylvania mines – hard minerals left by past mining and metallurgical industries in the commonwealth and minerals dissolved in acid mine drainage.
A report detailing the findings shows this investigation identified ore grade cobalt related to historical Pennsylvania coal and iron mining.
This includes roughly 0.114% cobalt in layers of clay underlying Pennsylvania coal seams.
Materia USA, a company formed for the very purpose of producing critical minerals from unconventional sources, is already advancing a project that recovers rare earths gallium, lithium, and other critical minerals from these under-clays while reclaiming Pennsylvania coal fields.
More information on this and other unconventional sources of critical minerals in the United States can be read at Unconventional critical mineral solutions in Data Mine North's Critical Minerals Alliances magazine.
Iron ore deposits in Pennsylvania also have cobalt. Pyrite concentrates from the Bethlehem Steel Grace Mine, which operated from 1958 until 1977, averages 0.68% cobalt, which is comparable to some of the highest-grade ore on Earth.
Recovering cobalt from Pennsylvania's historic coal and iron mines could help solve environmental and social issues plaguing EV and lithium battery manufacturers.
"Much of the world's supply of cobalt is mined in the Democratic Republic of the Congo, where approximately two-thirds of the raw cobalt reserves are located, and China is the world's leading cobalt refiner," said Barbara Arnold, professor of practice in mining engineering at Penn State. "The United States currently has virtually no domestic processing capacity, so the limited raw materials produced today are primarily shipped overseas for processing. Finding U.S. domestic resources for cobalt and other battery metals along with enhancing refining capacity is crucial."
In addition to cobalt, the study carried out for Penn State indicates that more than 5,500 metric tons of manganese are dissolved by acid mine drainage in Pennsylvania each year. If untreated, this metal-laden sludge will find its way into the commonwealth's waterways.
Acid mine drainage occurs when sulfide minerals react to air and water to form sulfuric acid. While this process sometimes occurs naturally, it can be more pronounced after mining if the exposed sulfides are not cut off from sources of water and air. Modern regulations require that sulfides exposed by mining are sealed from the atmosphere with water or rock after mining is complete. Such regulations, however, have only been in place for the past 50 years
"Acid mine drainage has been a significant environmental concern for many decades," said Mohammad Rezaee, assistant professor of mining engineering in the College of Earth and Mineral Sciences at Penn State, in relation to a 2020 breakthrough in recovering rare earths from acid mine drainage.
More information on a process developed by Penn State researchers to recover rare earths from acid mine drainage can be read at Acid mine drainage may offer rare earths in the August 12, 2020 edition of Metal Tech News.
The recovery of manganese, rare earths, and other critical minerals could pay the costs of treating acid mine drainage from legacy mining – another scenario that offers two wins for the environment and one for the economy of Pennsylvania.
"Recovery of these elements could provide domestically-sourced materials for the lithium-ion battery industry in the United States," Pisupati said. "In addition to the expected economic benefits, this can help remediate the environmental degradation caused by previous mining activities."