The prevention and mitigation of fugitive dust emissions from mine tailings surfaces depend largely on our ability to monitor and predict tailings moisture content (TMC). To do so, hyperspectral and multispectral methods are demonstrated here to be valuable tools to quantify TMC in bauxite residue samples under controlled conditions in the laboratory. The difference in albedo between 1.30 and 1.55 microns (Δ albedo) obtained through the InfraRed Integrating Sphere (IRIS) method matches that acquired with a field spectroradiometer while both are strongly correlated with TMC. In addition, continuous Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and Δ albedo analyses of evaporating bauxite residues reveal their surface drying rates. Comparing results from samples prepared with specific TMC with those from evaporating samples reveal how surface TMC can differ from the bulk due to processes such as precipitation, sedimentation and evaporation. These optical methods are shown to display adequate temporal and spatial resolutions opening up interesting prospects for the real-time monitoring and prediction of critical surface moisture conditions at mining residues disposal sites, important proxies for the prevention of fugitive dust emissions. Furthermore, such short-wave infrared ground base measurements could help validate remote sensing optical measurements of TMC thereby improving the accuracy of dust emissions risk assessment protocols that support mining industries intervention and mitigation strategies.

Monitoring and predicting moisture content and evaporation kinetics from mine tailings through hyperspectral and multispectral albedo measurements to help prevent fugitive dust emissions

ACS Spring Meeting 2021

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