Chapman access only Poster
California has a well-documented history of mining activity. The processes associated with mining for precious metals has yielded an increase in toxic inorganic arsenic levels in the mine wastes. Due to the relatively arid climate, the mobility and bioaccessibility of arsenic in these wastes are controlled by the size of the particle and arsenic concentration. This experiment intended to establish size and surface area trends in order understand the impact various mine wastes have on local communities. Three samples from the Randsburg Historic Mining District in Southern CA were used: Marigold East tailings, Marigold East waste rock, and Calico Mine tailings. Tailing samples were crushed and treated with various chemicals to extract precious metals while waste rock samples were mined but not processed. Samples were sieved into 11 distinct size fractions then analyzed for reactive surface area. Results indicated that the waste rock sample had a direct trend between its size and mass distribution with a max distribution of mass in the >2830um range. There was a direct trend between particle size and surface area in which the surface area increased with increasing particle size. Both tailings samples exhibited a unimodal trend between size and mass distribution with the max distribution of mass in the 74-45um range, however tailing samples exhibited alternate trends with surface area. The results indicated that there is an adverse impact to local communities near tailing samples due to the increase in bioaccessibility of toxic arsenic.
Cablay, Kory and Kim, Christopher S., "Mass Distribution and Surface Area Trends of Size Fractionated Arsenic-Bearing Mine Tailings" (2014). Student Research Day Abstracts and Posters. 65.