In Suriname, mercury amalgamation is the favored method for recovering fine gold from sluice concentrates. An estimated 12-16,000 miners are releasing as much mercury to the environment as they are recovering in gold. A project is now underway to reduce or eliminate the use of mercury in gold mining. Funded by World Bank and in partnership between Artminers and World Wildlife-Guianas, this project introduces the Cleangold™
sluice as an alternative to mercury. This patented method employs simple, inexpensive gravity separation. The University of British Columbia and University of Uppsala in Sweden have independently verified the efficacy of Cleangold. After field tests in Africa, Asia and South America, UNIDO’s Global Mercury Project has identified Cleangold as a mercury replacement method. A first round of training workshops were completed in
December 2005 with over 70 miners attending. Interest is high in Cleangold because miners are paying upwards of $300/kg for mercury. Testing the ores and tailings of the operations in two areas confirmed anecdotal accounts from miners that they are
recovering approximately 50% of the gold using their current practices. Using the Cleangold method, samples of gold, mercury, and amalgamated gold were recovered from tailings. The bulk of the gold recovered was found to be less than 150 microns in
diameter. While the sluice boxes used by these miners are well built and operated, gold below 150 microns is not recovered by their expanded metal and looped carpet sluices. Evidence of losses of gold larger than 150 microns during the amalgamation process was noted and a mechanism for this loss is suggested. Methods to completely remove the use of mercury from these operations are described. Miners who attended workshops intend
to employ Cleangold sluices to retrieve mercury, amalgam and fine gold from their tailings. This will be the first step in reclamation of abandoned mine sites. To reduce pollution from this process, WWF-Guianas will build simple retorts for distribution to miners to safely recover mercury from the concentrates of the Cleangold™ process until mercury free mining is established.
2006. s. 574-