Mercury balance in amalgamation in artisanal and small-scale gold mining: identifying strategies for reducing environmental pollution in Portovelo-Zaruma, Ecuador

Velásquez-López, Patricio C.; Veiga, Marcello M.; Hall, Ken J.

doi:10.1016/j.jclepro.2009.10.010

Cited by 95 publications

(53 citation statements)

References 28 publications

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“…The Au/Ag mining uses liquid Hg 0 to amalgamate Au/Ag ores. Mercury is evaporated by roasting the Au/Ag-Hg amalgam at temperatures >1000 °C to obtain Au/Ag (Robins and Hagan, 2012;Velásquez-López et al, 2010). This process involves a high-temperature, near-complete physical transformation of liquid Hg 0 to GEM, and should induce insignificant Hg MDF (Laffont et al, 2011).…”

Section: Intentional Hg Use Sectorsmentioning

confidence: 99%

Historical (1850–2010) mercury stable isotope inventory from anthropogenic sources to the atmosphere

Sun

Streets

Horowitz

et al. 2016

Elementa: Science of the Anthropocene

162

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Mercury (Hg) stable isotopes provide a new tool to trace the biogeochemical cycle of Hg. An inventory of the isotopic composition of historical anthropogenic Hg emissions is important to understand sources and post-emission transformations of Hg. We build on existing global inventories of anthropogenic Hg emissions to the atmosphere to develop the first corresponding historical Hg isotope inventories for total Hg (THg) and three Hg species: gaseous elemental Hg (GEM), gaseous oxidized Hg (GOM) and particulate-bound Hg (PBM). We compile d

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Section: Intentional Hg Use Sectorsmentioning

confidence: 99%

Historical (1850–2010) mercury stable isotope inventory from anthropogenic sources to the atmosphere

Sun

Streets

Horowitz

et al. 2016

Elementa: Science of the Anthropocene

162

View full text Add to dashboard Cite

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“…The use of retorts is a major way of reducing mercury loss after amalgamation (19,30,31,32,33). Several types of retorts are available in small-scale mining centres around the world, with the major ones being the steel and Thermex glass retorts (Figs 1 and 2).…”

Section: Interventions On Mercury Usementioning

confidence: 99%

A Lantern Retort for Small-Scale Gold Extraction

Amankwah¹,

Ofori-Sarpong

2014

IJEPP

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Abstract:Two major retorts used in small-scale gold mining operations to reduce mercury emissions, during amalgam distillation are the steel and thermex retorts. Steel retorts are not very popular due to the reported darkening of gold after retorting. In addition, its opaque nature prevents miners from observing the process directly. The Thermex glass retort introduced by the United Nations Industrial Development Organisation (UNIDO) is also not patronised due to the extended heating periods resulting from the low thermal conductivity of glass. This paper describes a new retort, the Lantern retort, a combination of highly conductive steel with transparent glass, and therefore, a potential solution to the above concerns. The Lantern retort has a shorter warm-up and amalgam distillation time, and the rate of heating is 1.81 o C/s while that of the Thermex is 1.49 o C/s. For an amalgam of mass 20 g, 900 s was required to carry out complete distillation in the Lantern retort as against 2100 s in the Thermex. The height of the distillation column of the Lantern retort required to reduce mercury loss to below 1%, as it is with the Thermex retort, is 2.5 cm. Other advantages of the Lantern retort are that, it is less expensive and can withstand the harsh terrain of small-scale gold mining.

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“…There have been few studies about the presence of metals resulting from mining in the Puyango River Basin [9][10][11][12], nevertheless, all talked about the influence of mining in the presence of metals in different parts of the rivers. These studies where focus on a circumscribed area of the basin, especially in the upper basin, the present study was conducted throughout the basin, including the origins of the rivers, the mining area, the middle Basin and the low Basin, near to the border with the neighboring country Peru.…”

Section: Introductionmentioning

confidence: 99%

Mining and Seasonal Variation of the Metals Concentration in the Puyango River Basin—Ecuador

García¹,

Betancourt²,

Cueva³

et al. 2012

JEP

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The Puyango River Basin covers approximately an area of 4400 km 2 , it is located in Southern of Ecuador, with Calera and Amarillo rivers as tributaries. In this region, one of the main activities is small scale gold and silver mining. Currently there are 110 processing plants on the bank of Calera and Amarillo rivers, causing a significant degradation of natural resources. A seasonal comparison of metal concentrations in surface water, sediments and particulate matter from the Puyango River and its effluents is made. It was done a differentiation between natural contaminations with the anthropogenic one generated by mining activity. Samples were taken during dry season (2004) and rainy season (2006), and analyzed physicochemical parameters, anions and cations and the concentrations of heavy metals. The results show a clear influence of gold mining in Puyango River contamination, starting with its tributaries, Calera and Amarillo rivers, which have the highest concentrations of heavy metals from the basin, corresponding with the location of the mineral processing plants.

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Mercury balance in amalgamation in artisanal and small-scale gold mining: identifying strategies for reducing environmental pollution in Portovelo-Zaruma, Ecuador

Cited by 95 publications

References 28 publications

Historical (1850–2010) mercury stable isotope inventory from anthropogenic sources to the atmosphere

Historical (1850–2010) mercury stable isotope inventory from anthropogenic sources to the atmosphere

A Lantern Retort for Small-Scale Gold Extraction

Mining and Seasonal Variation of the Metals Concentration in the Puyango River Basin—Ecuador

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