The Development of a Laboratory-Based Method to Simulate Cold-Weather Dusting on Mine Tailings Impoundments

Mining produces approximately 14 billion metric tons of tailings annually, mainly deposited into surface impoundments as a slurry of water and silt-sized materials. An environmental problem during dry summers is dust emissions generated during high winds. However, large dust storms can also develop during cold weather, particularly in the fall and spring. During initial freezing periods, typically at night, the surface of the tailing becomes frozen. In the morning, as temperatures rise above freezing, the frozen tailing surface can rapidly sublimate under certain atmospheric conditions, generating a layer of desiccated tailings overlying frozen tailings. The dried surface tailings become susceptible to wind erosion and large-scale dust storms. The rapid sublimation of the mine tailings, however, is poorly understood. This research develops methods to simulate cold weather dusting from a mine tailings impoundment in a laboratory. The dust emissions and strength of tailings samples are characterized using a wind tunnel and ball drop testing, respectively. These laboratory methods can be used in research to understand better the coupled phenomena of ice lens generation, sublimation, and dust generation for fine-grained sediments.