Reducing mercury pollution by training Peruvian artisanal gold miners Marcello M. Veiga a, * , Gustavo Angeloci a , Wilmer ~ Niquen b , Jacopo Seccatore c a Norman B. Keevil Institute of Mining Engineering, University of British Columbia, Canada b UBC-US Department of State Project, Peru c Department of Mining & Petroleum Engineering, University of S~ ao Paulo, Brazil article info Article history: Received 27 June 2014 Received in revised form 26 January 2015 Accepted 27 January 2015 Available online 12 February 2015 Keywords: Artisanal mining Gold Mercury Training Peru Piura abstract In 2010, in the Piura region, north of Peru, 10,000 artisanal miners and more that 160 processing plants were dispersed in 158,000 ha applying extremely primitive techniques to extract gold using 5 to 10 t of mercury to amalgamate the whole ore. The US Department of State and the University of British Columbia established a project to train miners from 2010 to 2013 on mining and processing methods. A demonstration plant in Portovelo, Ecuador was used to train 46 Peruvian, 50 Colombian and 115 Ecua- dorian small miners and processors on methods to reduce and eliminate mercury increasing gold re- covery by gravity concentration, flotation and cyanidation. Miners had the opportunity to learn unit operations of mining engineering and they realized that their rudimentary processes were very ineffi- cient to extract and recover gold from complex sulphide ores. Ore buyers in the Piura region provide a better deal for the miners who are currently selling their ores for 50% of the gold content analyzed by local chemical labs. By selling to ore buyers, miners have in their hands, at the end of one day, more money than if they had amalgamated the ores. Due to this fact and through education, mercury levels in the region were reduced at least by 50% from the 2010 levels. A pre-feasibility study of a small processing plant operating with gravity concentration, flotation and cyanidation of the concentrates revealed that with Au grade equal or above 10 g/t, evenwith 50% of gold recovery and at USD 1300/oz of Au, a 10 t/day plant is still profitable. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Worldwide around 16 million artisanal gold miners produce between 380 and 450 t (metric tonnes) of gold annually in at least 70 countries (Seccatore et al., 2014). Artisanal gold mining (AGM) is not always small in spite of the large incidence of micro-miners processing 20 kg of ore per day and recovering 0.1e0.5 g of gold. However, worldwide, there are many artisanal operations pro- cessing as much as 5000 tpd (metric tonnes per day) of ore and extracting 0.5e3 kg of Au per day (Veiga et al., 2014a). The term “artisanal” should refer to the use of rudimentary techniques in mining and processing and not to the size of the operation. There is a common perception from the general public that all artisanal miners are small (panners) and illegal (Veiga, 1997). The number of artisanal gold miners in rural areas of developing countries has been increasing due to the harsh living conditions and high gold price. Governments are usually not prepared to train the miners or are present to enforce environmental and mining laws (Hilson, 2002, Banchirigah, 2006; Hilson and Vieira, 2007). Mercury contamination of the land, aquatic life and community members is an issue often raised in the literature (Akagi et al., 2000; van Straaten, 2000; Drasch et al., 2001; Hilson and Pardie, 2006; Hilson and Vieira, 2007; Swain et al., 2007; B€ ose-O’Reilly et al., 2008; Guimar~ aes et al., 2011; Guiza, and Aristizabal, 2013). AGM are currently the largest mercury consumers in the world with 1400 t/a (metric tonnes per year, UNEP, 2013). Monitoring of mer- cury pollution has been the main focus of the environmental pro- jects on AGM but unfortunately very few solutions have been implemented or even suggested (Hinton et al., 2003; Hilson, 2006; Hilson et al., 2007). Miners are not impressed with results of health and environmental monitoring programs and this approach is not persuasive for them to make changes in their rudimentary polluting methods. Capacity building and demonstration of cleaner techniques must be the focus of the interventions. Miners only pay * Corresponding author. E-mail addresses: veiga@mining.ubc.ca, veiga@apsc.ubc.ca (M.M. Veiga). Contents lists available at ScienceDirect Journal of Cleaner Production journal homepage: www.elsevier.com/locate/jclepro http://dx.doi.org/10.1016/j.jclepro.2015.01.087 0959-6526/© 2015 Elsevier Ltd. All rights reserved. Journal of Cleaner Production 94 (2015) 268e277