240 - A Comprehensive Review on Gold Production, Mercury Consumption and Emission in Artisanal and Small-scale Gold Mining (ASGM)

In 2017, the Minamata Convention on Mercury entered into force. As one of the largest sources of Hg emission, artisanal and small-scale gold mining (ASGM) is critical to tackling the Hg problem. However, due to its informal nature, data on ASGM production and consumption of Hg in the process are hard to obtain. The current state of global ASGM activity and the potential risk in Hg governance is not clear. In this study, we reviewed existing literature thoroughly to provide a whole picture of the Hg use and emission in the ASGM sector. Specifically, we summarized methods for the calculation of ASGM production and determined the approximate scale of ASGM production on the global scale and region levels.

According to our review of papers, dominant methods for the calculation of ASGM production include three different types. Method 1 estimates ASGM production based on the number of miners in ASGM and the productivity for each miner; method 2 estimates the gold production from ASGM based on its ratio to the total gold production from officially reported data; method 3 subtracts gold produced by conventional gold mining companies from the total global gold production.

From the results obtained using different methods, the scale of ASGM production is consistent. Globally, ASGM produces 379.4–871.2 tonnes of gold each year. At the regional level, the newest estimate shows a significant increase in Asia from 120 tonnes in 2011 to 304.1–479.4 tonnes in 2015, with extreme increases existing in China and Indonesia, and a slight increase in Africa from 85–90.4 tonnes to 126.5–178.4 tonnes. ASGM production in Central and South America is relatively stable with an estimate of 184.7–213.4 tonnes in 2015. ASGM activities occurred more often in countries with lower human development indicator rankings and had lower high-skill employment.