45 Critical Reviews in Environmental Science and Technology, 33(1):45–71 (2003) 1064-3389/03/$.50 © 2003 by CRC Press LLC A Review of Environmental Considerations on Gold Mining and Production Aysen Müezzinoˇ glu Dokuz Eylül University, Faculty of Engineering, Department of Environmental Engineering, Kaynaklar Campus, 35160 Buca, Izmir, Turkey. Telephone and fax: ++90 232 453 0922; e-mail: aysen.muezzin@deu.edu.tr ABSTRACT: Gold mining is attracting increasing attention in many countries of the world, although it has a major impact on the environment. Large quantities of hazardous chemicals such as mercury or sodium cyanide are consumed to recover gold from its ores. Therefore, this activity should be carefully regulated by means of global directives based on an up-to-date knowledge of ecotoxicity principles and modern environmental standards. This article summarizes the basic information on past and present environmental impacts of gold production. Novel methods, possibly with reduced environmental risks, are briefly mentioned. Global regulatory criteria for minimization of the ecological and human health risks in mining, production, and processing facilities are proposed. Articles from different scientific disciplines distilled from the experiences of actual gold mining operations are cited. The most recent information gathered during the last 10 years of discussions regarding gold prospecting and recovery in Turkey has been added to them. KEY WORDS: gold mining, environmental impacts of gold mining, amalgamation, cyanide leach process, wastes, global directives for gold mining. I. INTRODUCTION Gold, as a symbol of prosperity and wealth, has always been an asset since the Bronze Age. Therefore, a thorough understanding of the impact of gold mining must take into account the history, legend, and culture, as well as a sound knowl- edge of the economy and social values of the past and present communities. It was recorded that gold concentration in the upper layer of the Earth is around 4 mg t –1 (ppb). The largest amount of gold is present in the oxide shell as pure gold or gold tellurite and gold selenite. Hydrothermal mechanisms bring it to the surface. 31 The main gold mineral types are alluvial, rock, and combination forms. 13 It is reported by Jewett et al. 25 that, in addition to the mining options on land, explorations are going on to recover gold from sea beds, too. Korte and Coulston 31 suggested that since many “real gold mines” working with large pieces have been exhausted today, chemical processes with extensive use of aggressive or hazardous chemicals have to be used for gold mining. They 130359.pgs 1/13/03, 12:37 PM 45