Assessing the environmental impact of gold production from double refractory ore in a large-scale facility

Abstract

Despite the strict environmental management regulations, there is still a considerable adverse impact on the ecosystem and human health when it comes to large-scale gold mining operations. Gold mining is an energy-intensive process that can discharge substantial quantities of chemicals combined with gaseous emissions into the environment. Considering gold mining's significant role in Nevada's economy and the growing concern about climate change, it's necessary to investigate the environmental burdens of this sector. To provide a comprehensive environmental perspective on the large-scale gold mining operations in Nevada, this study used a life cycle assessment (LCA) approach to evaluate the environmental burdens of gold production from double refractory ores in the roasting process. The Tool for Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI) method was used to evaluate the categories of acidification, ozone depletion, global warming, smog, carcinogenics, non-carcinogenics, respiratory effects, and fossil fuel depletion. Results showed that major contributors to greenhouse gas (GHG) emissions were grinding and off-gas treatment stages being responsible for 34.80 % and 56.10 % of the total global warming, respectively. The carbon footprint for producing one kg of gold was 12,200 kg CO2-eq. Sensitivity analysis was also employed on electricity to observe the influence of electricity on key contributor stages. A 10 % change in electricity reduced the GHG emissions in crushing and grinding by 12.2 % and 7.10 %, respectively, while delivering an insignificant effect on the off-gas treatment. Significantly, this study stands as the first initiative to apply LCA in the North American mining industry, with a unique focus on the off-gas treatment post-roasting and its associated emissions. Our findings can serve as a foundational database, aiding stakeholders in making informed decisions and enhancing sustainable practices in the gold mining industry.