Simulation of windblown dust transport from a mine tailings impoundment using a computational fluid dynamics model Michael Stovern a , Omar Felix b , Janae Csavina b , Kyle P. Rine a , MacKenzie R. Russell a , Robert M. Jones a , Matt King a , Eric A. Betterton a,b , A. Eduardo Sáez b,⇑ a Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, United States b Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, United States article info Article history: Available online xxxx Keywords: Aerosol transport Dust Deposition CFD Superfund abstract Mining operations are potential sources of airborne particulate metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, due to potential deleterious effects on human health and ecology. Dust emissions and dispersion of dust and aerosol from the Iron King Mine tailings in Dewey-Humboldt, Ari- zona, a Superfund site, are currently being investigated through in situ field measurements and compu- tational fluid dynamics modeling. These tailings are heavily contaminated with lead and arsenic. Using a computational fluid dynamics model, we model dust transport from the mine tailings to the surrounding region. The model includes gaseous plume dispersion to simulate the transport of the fine aerosols, while individual particle transport is used to track the trajectories of larger particles and to monitor their depo- sition locations. In order to improve the accuracy of the dust transport simulations, both regional topo- graphical features and local weather patterns have been incorporated into the model simulations. Results show that local topography and wind velocity profiles are the major factors that control deposition. Ó 2014 Published by Elsevier B.V. 1. Introduction The Iron King mine tailings site located in Dewey-Humboldt Arizona is a potentially hazardous source of contaminated aerosols. The Iron King Mine tailings and nearby inactive smelter site were officially added to the Environmental Protection Agency (EPA) na- tional priorities list in 2008. The smelter was operational from 1904 till 1969. It was used to extract lead, gold, silver, zinc and copper at different times. The 220,000 m 2 tailings were impounded on property (EPA, 2010). Sediment from these mine tailings has significantly elevated concentrations of both lead (up to 0.20 wt%), and arsenic (up to 0.24 wt%), amongst other toxic spe- cies. Additional tests of top soil from nearby sampling sites have shown elevated contaminant concentrations outside the bound- aries of the Iron King Mine property. The spread of the contami- nants is in part caused by aeolian dust transport from the mine tailings. Aerosol and dust transport is a potentially dangerous mecha- nism for spreading contamination because of the high mobility of the smaller suspended particulate, especially for accumulation mode aerosols (<1 lm diameter). This particle size range is poten- tially hazardous to human health since they have the potential to deeply penetrate in the respiratory system. The relatively large dif- fusivity of these aerosols causes them to have an increased likeli- hood to deposit in the smaller airways such as the alveolar regions of the lungs (Hinds, 1999). Long-term exposure to these aerosol and dust particles may cause adverse health effects. Life- time excess cancer risks for a similar arsenic contaminated copper mine located in Hayden, Arizona, was estimated to be 1 in 5000 by the Arizona Department of Health Services (Public Health Assess- ment, 2002), and up to 1 in 100, as estimated by EPA (Earth Justice, 2003). In this work, we apply a Computational Fluids Dynamics (CFD) software tool, ANSYS FLUENT, to investigate aeolian transport and deposition rates of aerosols emitted from the Iron King Mine tail- ings to the surrounding region. The CFD is based on the turbulent Reynolds Averaged Navier-Stokes (RANS) equations. The complex topography of the terrain in the simulation area is included in the model. In addition, this CFD model can track both mixed gaseous species as well as predict the trajectories of individual http://dx.doi.org/10.1016/j.aeolia.2014.02.008 1875-9637/Ó 2014 Published by Elsevier B.V. ⇑ Corresponding author. Address: Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Harshbarger 108, Tucson, AZ 85721-0011, United States. Tel.: +1 520 621 5369. E-mail address: esaez@email.arizona.edu (A.E. Sáez). Aeolian Research xxx (2014) xxx–xxx Contents lists available at ScienceDirect Aeolian Research journal homepage: www.elsevier.com/locate/aeolia Please cite this article in press as: Stovern, M., et al. Simulation of windblown dust transport from a mine tailings impoundment using a computational fluid dynamics model. Aeolian Research (2014), http://dx.doi.org/10.1016/j.aeolia.2014.02.008