TRANSPORT MECHANISMS OF METAL-BEARING HISTORIC MINE TAILINGS IN A SEMI-ARID ENVIRONMENT

Tellurium (Te) is an energy critical element that can be enriched in mine tailings residual from gold extraction (up to ~300 mg kg^-1). Under surficial conditions, Te in mine tailings undergoes oxidative weathering and is also susceptible to wind and water transport. Very little is known about the behavior of Te in the surficial environment, but some forms of Te are known to be more toxic than arsenic and selenium. The potential toxicity combined with mass transport of Te-bearing particles by wind or water raises concerns regarding nearby ecosystem, environmental, and human health. Release of metal(loid)s to the environment from mine tailings has degraded ecosystem vitality and community health.

The goal of this project is to assess the mass transport of Te and other toxic metal(loid)s by wind and water from semi-arid mine tailings in the historic Delamar Mining District in Lincoln County, NV. Samples were collected from a 0-2 cm depth along 8 transects (8 samples each) centered at the largest tailings pile to assess local wind transport. An additional 10 samples were collected along a dry streambed downstream of the site to assess surface water transport of the tailings toward a playa used for off-road recreational driving. The elemental composition of all samples was determined using wavelength dispersive-X-ray fluorescence (WD-XRF) to examine patterns of metal(loid) dispersion. The results reveal that patterns of metal dispersion are complicated by anthropogenic activities in the area. HYSPLIT modeling indicates that the predominant wind travels from southwest to northeast, but short-term anemometer data suggests wind direction at the site may be complicated by local topography. Together, these results represent an important first step toward understanding the potential impacts of Te on the environment.