Date of Award

2016

Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Civil Engineering (PhD)

Administrative Home Department

Department of Civil and Environmental Engineering

Advisor 1

Eric Seagren

Advisor 2

Thomas Oommen

Committee Member 1

Stan Vitton

Committee Member 2

Ann Maclean

Abstract

Mining operations produce massive volumes of mine tailings, which are deposited as slurry into permanent tailings impoundments. An important and heavily regulated environmental hazard associated with mine tailings impoundments is fugitive dust emissions. Wind erosion of mine tailings impoundments and the resulting dusting events, especially those caused by cold weather dusting, remain an on-going challenge for the mining industry. The overall goal of this research was to develop and evaluate effective, economical, and sustainable solutions to two major issues facing mine tailings impoundments with regards to dusting: (1) dust monitoring/detection and (2) dust reduction/prevention. Specifically, the research studied iron mine tailings and used (1) laboratory and field testing to assess the utility of thermal remote sensing techniques for dust monitoring, and (2) laboratory testing to assess the ability of biological soil crusts to reduce dust emissions due to cold weather dusting. A laboratory model was developed to use thermal remote sensing and other atmospheric variables to predict surface moisture content and strength of iron mine tailings. Though this relationship was not found to be directly applicable to field remote sensing, this research suggests that a model could be developed using field data to predict surface moisture content using thermal remote sensing, which would be a useful tool for tailings impoundment managers to employ for dust emissions detection. Additionally, a method was developed and validated that exposed laboratory tailings sample to freezing and sublimation conditions that are representative of those experienced at tailings impoundments located in cold-weather climates, and the dust emissions and strength of these tailings samples was characterized using wind tunnel and ball drop testing. Lastly, biological soil crusts originating from locally-sourced organisms were grown on laboratory tailings samples, and when exposed to freezing/sublimation and tested with wind tunnel and ball drop testing, the biological soil crusts were found to provide resistance to wind erosion and increased surface strength. These results are important, both for the understanding of dust emissions and potential dust mitigation treatments for tailings impoundments, and also for broader issues of wind erosion and dust emissions of soil both globally and on other planets.

Available for download on Tuesday, August 01, 2017

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