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scientists sampling water
Sampling at a historical mining waste pile with associated drainage. Photograph by USGS.

Why is USGS conducting this research?

Many metals that in the past had a limited to modest industrial or technological application are now critical for emerging high-technology or green-technology applications. Increasing demand for these critical metals, coupled with their geologically rare economic enrichments in the earth's crust, has raised concern about their availability. Recovery of these metals from waste materials is increasingly of societal interest, as it may help reduce dependence on foreign sources for the metals, defray costs of waste remediation, reduce the content of metal toxicants in wastes, and diminish needs for mining that specifically targets the metals.

Previous work on the Metal and Mineral Commodities in the Built and Waste Stream Environments—Uses, Characteristics, and Environmental/Health Implications project examined the types, concentrations, and environmental and toxicological characteristics of metal and minerals in a wide range of building materials and other materials found in buildings such as concrete blocks, brick, rebar, concrete, pipes, plastics, electronics, and pressure treated lumber. Results revealed a number of unusual occurrences of metals and minerals.

How is our research addressing this issue?

This project explores potential recovery and environmental consequences of metals in mining and mineral processing wastes as a function of ore deposit geology, and in debris from demolished or burned buildings. Our general objectives are to 1) characterize metals in bulk materials; 2) examine the leachability of metals from these materials; 3) examine deportment of metals during smelting or refining, and 4) tie metals in these materials to the life cycle of mineral commodities from extraction, through manufacturing, consumer use, reuse, recycling, and disposition.


Project Activities

Metals and Minerals in Debris from the Built Environment

Contact: William Benzel,

Our primary objectives are to 1) understand the forms, concentrations, and environmental implications of metals in materials that are recycled or sent to landfills when buildings are demolished or have burned, 2) screen previously collected samples by portable X-ray fluorescence, from which 24 samples will be sampled for further analysis, and 3) burn site materials will be analyzed and compared to lumber of varying age.

Sources, Forms, and Extractability of Mining and Mineral Wastes

Contact Philip Hageman,

Our objectives are to 1) obtain additional mining waste samples from a variety of mineal deposits types, 2) conduct bulk chemical and mineralogical characterization of the waste samples, and 3) subject waste samples to leaching tests to determine extractability of elements of interest.

Sources, Forms, and Extractability of Metals from Smelter Wastes

Contact: Nadine Piatak,

We will examine deportment of metals during smelting or refining. Our objectives are to 1) conduct bulk chemical and mineral characterization of modern smelter slag, 2) identify amounts and modes of occurrence of residual elements in slag for potential recovery, and 3) quantify deportment of various metals during processing steps of concentrating metals from ore in order to optimize recovery.

Macro-Analytical Methods for the Determination of Platinum Group Elements, Gold, and Silver in High Organic Matrices

Contact: LaDonna Choate,

Our objectives are to develop new techniques and methods for the determination of platinum group elements (PGEs), gold, and silver in high organic materials. We will investigate digest procedures to eliminate concentration discrepancies of platinum group elements between analytical methods previously used on bio-solids. Methods and modifications of the digest-concentration procedures will be tested and analyzed with various analytical techniques.




Smith, K.S., Plumlee, G., Hageman, P.L., 2015, Mining for metals in society’s waste: The Conversation, posted October 1, 2015,


Bowell, R., Smith, K.S., Plumlee, G.S., Hageman, P.L., Kleinmann, R., 2016, Metal Recovery from Mine Waters: Feasibility and Options – an Example Assessment from the Colorado Mineral Belt, USA. in Drebenstedt, C., and Paul, M.: International Mine Water Association (IMWA) 2016 – Mining Meets Water – Conflicts and Solutions, Leipzig, Germany, July 11-15, 2016, p. 1263-1266. View Bowell abstract. [PDF file, 1.5 MB]

Hageman, P.L., Smith, K.S., Wolf, R.E., Plumlee, G.S., and Orkild-Norton, A.R., 2016, Potential recovery of critical elements from historical metal mining waste: the effectiveness of using various leachants to extract precious metals, platinum group elements, selected rare-earth-elements, and various industrial minerals: Geological Society of America Abstracts with Programs, Vol. 48, No. 7, doi:10.1130/abs/2016AM-285433.

Smith, K., Hageman, P., and Plumlee, G., 2017, Characterization of Historical Metal Mining Wastes for Potential Metal Recovery: 2017 SME Annual Conference and Expo and CMA 119th National Western Mining Conference, February 19-22, 2017, Denver, CO, p. 57.


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