Our science is helping answer the question: how do we mitigate the hazards left behind by a legacy of mining, and how can we use what’s left as a resource? 

The American landscape is scattered with signs of past mining. These remnants, some of which are over 200 years old, include historic mining infrastructure, old adits and quarries, and piles of rock and mineral that were left behind after the desired minerals were extracted and processed. 

Mine Wastes as Hazard; Mine Waste as Resource

These features can be hazards to environmental health and human safety. For instance, mine waste piles can contain chemicals like arsenic that can leach into waterways. Adits and mine shafts can be unstable, and potentially harm hikers or others. 

Mine wastes also often contain valuable minerals like rare earth elements. These minerals were left behind because they were not profitable enough or technologically feasible to extract and process. Today however, these sources of minerals could supplement traditional mineral development, providing a way of strengthening domestic mineral supply chains while reducing the environmental footprint of mining.

Our science is revealing the landscape that a legacy of mining has created.

Our USMIN project is inventorying mine features of all kinds across the U.S. to identify features that could be hazardous and features that might be reutilized as a resource. So far, we have documented over 170,000 documented mine features in the U.S. We are also currently working towards the Nation’s first inventory of mine waste features – a fundamental cornerstone for evaluating the potential for recovering valuable minerals from mine wastes. 

Through Earth MRI, we are also collecting data to fill in gaps in our understanding of where mine wastes might be, and what their resource potential is. We are developing high-resolution maps of the geology, topography, and spectral (light) patterns of the Earth’s surface and developing novel methods for using this data to identify mine wastes on the Earth’s surface. We are also studying the geochemical characteristics of known mine wastes to determine how much mineral content these wastes might contain. 

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Our science is helping decision-makers to understand modern-day mine waste streams and their resource potential. 

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Our research includes quantifying and characterizing the mineral content of modern mine waste streams. One example of our research is partnering with active mines to characterize the mineral content of their waste streams. 

We also study the supply chains of “byproduct minerals” – minerals that are primarily produced as a secondary product at mines focused on extracting a different mineral. Byproduct minerals can have unstable supply chains because their production is reliant on the production of a separate mineral – and changes in demand for that mineral. 

Our science on the geologic and economic relationships between primary and byproduct minerals inform decisions about how to strengthen supply chains of crucial byproduct minerals. 

We study how legacy and modern mine wastes interact with the environment, especially with water resources. 

Solid mine wastes can contain materials that, when leached into soil or water, can be detrimental to ecosystem and human health. These include materials like mercury, arsenic, or iron sulfide minerals that, when exposed to oxygen, water and microbes, produce an acidic solution. 

Our science provides information about what materials mine wastes contain, how these materials are mobilized and transported through natural processes and disruptions like floods and fires, and where they might end up. We work closely with science and land management partners to understand the impacts that mine wastes have on ecosystems, including in soils and waterways, and to inform remediation decisions at specific mine waste sites.