Research by Reid Brown, who completed his master’s degree with Dr. Daniel Cadol, New Mexico Tech Earth & Environmental Science Department, in 2017.This research is one of several Energize New MexicoEPSCoR projects focusing on uranium mineralization and mine-site remediation.
Understanding the relationship of dust to uranium contamination can be critical to predicting if and how uranium moves by dust from a mine site, as well as predicting if the health of nearby community members and mine workers can be affected by mining activities. In this study, dust traps were installed at several locations at Jackpile Mine, a remediated uranium mine site at Laguna Pueblo, New Mexico, to evaluate this problem. In all samples, uranium levels were low, however, they were statistically high enough to help researchers determine dust influences on the movement of uranium. Several dust characteristics and their impact on uranium transport were studied:
- Can uranium levels vary with dust size?
- Can uranium levels vary with the height dust is carried?
- Does the shape of the landscape and vegetation type play a role?
- What role does soil moisture hold?
Results of the study indicate that uranium concentrations increase with the smallest grain sizes. Since smaller particles can be carried further, uranium can be carried further as well. This study also confirms that higher sampling heights have higher uranium levels. We also learned that dust distribution is controlled by the landscape, vegetative cover, and wind velocity. Three trends were observed: 1) There were high uranium soil levels in the valleys, 2) higher uranium soil levels in areas covered by juniper / pinyon woodlands; and 3) higher uranium concentrations are associated with denser vegetation, likely caused by denser vegetation slowing wind velocity leading to increased dust deposition. We were unable to determine if vegetation size played a critical role in dust mobility. Soil moisture may also reduce the movement of dust.
The results of this study support dust-control protocols at modern-day mines and at locations with naturally-high uranium concentrations in sediments, and for interpreting occurrences during historical mining activities.
New Mexico EPSCoR (Experimental Program to Stimulate Competitive Research) is intended to improve the state’s ability to do scientific research. It is funded by National Science Foundation (NSF) award #IIA-1301346.
References
- Brown, R. D., 2017, Geochemistry and transport of uranium-bearing dust at Jackpile Mine, Laguna, New Mexico, unpublished Masters of Science Thesis, New Mexico Institute of Mining & Technology, 101p. [posted with the permission of the author]