Environment & Energy

Mine Waste in the Eastern Adirondacks May be Untapped, Accessible Source of Rare Earth Element Minerals

By Communications and Publishing December 22, 2020

Waste rock from long-closed mines in the eastern Adirondack Mountains, New York, may prove valuable due to its rare earth element content, according to newly published research. The results are from airborne and ground surveys conducted by the U.S. Geological Survey and collaborators.

Rare earth elements are critical for advanced technologies such as cell phones, supermagnets, computers, medical apparatus, renewable energies and advanced defense systems. Currently, the U.S. depends heavily on imports for rare earth mineral resources.

“The possibility of accessing rare earth elements from mine waste and mill tailings is attractive partly because the minerals have already been excavated from the ground,” said USGS scientist Ryan Taylor, who led analyses of rock samples from the region. “This would reduce mining costs by making it easier to access the minerals. It also allows ‘recycling’ of discarded materials, which could help to remediate these mined areas,” he said.
USGS scientists were able to detect both mineral deposits and larger mill tailings piles from airplane surveys of old iron mines that occurred in December 2015. They then analyzed samples that showed rare earth content from the deposits, waste and mill tailings.

The eastern Adirondack Mountains in upstate New York were heavily mined for iron in the 1800s and 1900s and played an important role in industrialization of the Northeast prior to and during World War II. The mining activities resulted in piles of waste rock and mill tailings (the residuals of ore processing) in various areas throughout the region.

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