Thermal remote sensing for mine tailings strength characterization
Mine tailings impoundments are among the largest earthen structures in the world. One important and heavily regulated environmental hazard associated with tailings impoundments is air pollution from blowing tailings dust. Dust emissions occur when the shear stress exerted by the wind exceeds the frictional and cohesive forces that are holding the surface tailings in place. Therefore, understanding the strength properties of the upper few centimeters of the tailings is most critical for characterizing the susceptibility of tailings to dust emissions. The traditional approach for monitoring the susceptibility of mine tailings to dust emission includes collecting dust samples from monitoring stations, which are limited to a tiny sampling area. Additional limitations for dust emissions monitoring include cost, security issues, and trafficability issues. These limitations often lead to areas that are susceptible to dust emissions going unnoticed until the dust storm occurs. Thermal remote sensing may prove useful to more thoroughly monitor the surface strength, and therefore the susceptibility to dusting, of mine tailings. In this study, laboratory experiments were performed to measure the thermal properties of mine tailings by thermal remote sensing (yielding apparent thermal inertia, or ATI). These thermal properties were compared with the thermal properties obtained by traditional laboratory methods (yielding thermal inertia, or TI). The relationship between the thermal properties (ATI and TI), moisture content, and near surface strength was then explored. These preliminary results show that the thermal properties (ATI and TI) of the mine tailings are inversely related to the moisture content, and that the strength properties of the mine tailings increase significantly with a decrease in moisture. With this data, an indirect relationship can be developed between thermal remote sensing data (ATI) and surface strength, which demonstrates the potential utility of thermal remote sensing for predicting the near-surface strength of mine tailings. © 2014 American Society of Civil Engineers.
Geotechnical Special Publication
Thermal remote sensing for mine tailings strength characterization.
Geotechnical Special Publication(234 GSP), 979-988.
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