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ARS Home » Pacific West Area » Corvallis, Oregon » Forage Seed and Cereal Research Unit » Research » Publications at this Location » Publication #399183
Research Project: Improving Plant, Soil, and Cropping Systems Health and Productivity through Advanced Integration of Comprehensive Management Practices

Location: Forage Seed and Cereal Research Unit

Title: Designing amendments to improve plant performance for mine tailings revegetation

Author
item JOHNSON, MARK - Us Environmental Protection Agency (EPA)
item OLSZYK, DAVID - Us Environmental Protection Agency (EPA)
item BOLLMAN, MICHAEL - Us Environmental Protection Agency (EPA)
item NASH, MALIA - Us Environmental Protection Agency (EPA)
item Manning, Viola
item Trippe, Kristin
item Watts, Donald - Don
item Novak, Jeffrey

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/19/2023
Publication Date: 8/30/2023
Citation: Johnson, M., Olszyk, D., Bollman, M., Nash, M., Manning, V., Trippe, K.M., Watts, D.W., Novak, J.M. 2023. Designing amendments to improve plant performance for mine tailings revegetation. Journal of Environmental Quality. Volume 6, Issue 3. https://doi.org/10.1002/agg2.20409.
DOI: https://doi.org/10.1002/agg2.20409

Interpretive Summary: While mining provides valuable metals and minerals for industrial, agricultural, and other societal needs, mining activity can cause environmental damage. Extensive environmental damage arises from post-processing waste materials known as tailings. Tailings are often acidic and laden with heavy metals. When tailings are applied aback to the surface of hard rock mines, these properties make it challenging to establish plant communities to reclaim mine sites. This paper describes a case study of the Formosa Mine in Douglas County, Oregon, where tailings were amended with a mixture of lime, biosolids, biochar and microbial inoculum to facilitate establishment of Douglas-fir (Pseudotsuga menziesii [Mirbel] Franco) seedlings. Results show that the amendments counteracted changes to the soil made by the tailings. Two years after the soils were amended, the soil reacidified in some downslope locations, and was associated with an increase in tree mortality. This suggests that tailings conditions should be monitored and amendments should be reapplied as needed, particularly in areas receiving runoff from unamended upslope tailings. This study not only provides a prescription for addition of biochar and other amendments to enhance plant growth for revegetation purposes in acidic, metal-contaminated mine tailings, it also demonstrates a method to address similar problems at other mine sites.

Technical Abstract: While mining provides valuable metals and minerals to meet societal demands, it can cause environmental contamination from unstable mining residuals (tailings). Tailings are often acidic, laden with heavy metals, and lacking adequate nutrients and physical conditions for plant growth, precluding the establishment of plant cover to reduce the offsite movement of mining wastes. This paper describes a case study of the Formosa Mine in Douglas County, Oregon, where tailings were amended with a mixture of lime, biosolids, biochar and microbial inoculum to facilitate establishment of Douglas-fir (Pseudotsuga menziesii [Mirbel] Franco) seedlings. Results show that the tailings pH increased, and Douglas-fir seedlings survived and grew with these amendments. After two years, pH did, however, decrease in some downslope locations, and was associated with an increase in tree mortality. This suggests that tailings conditions should be monitored and be reapplied as needed, particularly in areas receiving runoff from unamended upslope tailings, until the seedlings are fully established. This study not only provides a prescription for addition of biochar and other amendments to enhance plant growth for revegetation purposes in low pH, metal-contaminated mine tailings, it also demonstrates a method to address similar problems at other mine sites.