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PROJECT SITE:  El Callao, Bolivar State




Uniidades de Demonsttraciión y Campaña de Educaciión para Miineros Arttesanalles de Oro.

Introducción de Tecnologías Limpias en la Minería Artesanal de Oro. II FORO INTERNACIONAL SOBRE LA MINERIA DEL ORO EN PEQUEÑA ESCALA. Ciudad Guayana, Venezuela.  Author: Pablo Huidobro, ONUDI (12-13 de mayo 2006)

Mercurio y Enfermedades Inmunológicas en Comunidades de Minería Artesanal de Oro: Una Interacción Peligrosa?  II FORO INTERNACIONAL SOBRE LA MINERIA EN PEQUEÑA ESCALA. Author: Janis Shandro, Dept Mining Engineering University of British Columbia (12-13 de mayo 2006)

Contaminación por mercurio en la minería artesanal en el Bloque B de El Callao: Evaluación de la salud.  II FORO INTERNACIONAL SOBRE LA MINERIA EN PEQUEÑA ESCALA.  Author: R. Darío Bermúdez Tirado, UNIDO (12-13 de mayo, 2006)

Mercurio y Cianuro en Minería Artesanal de la Provincia de El Oro, Ecuador Ing. Author: Patricio C. Velásquez, UNIDO and University of British Columbia. (12-13 de mayo, 2006)

Mercury Pollution from Artisanal Gold Mining in Block B, El Callao, Bolivar State, Venezuela: Health and Technological Assessment.  Authors: Marcello M. Veiga, Vienna Dario Bermudez, Heloisa Pacheco-Ferreira, Luiz Roberto Martins Pedroso, Aaron J. Gunson, Gilberto Berrios. (May, 2004).

Mercury Pollution from Artisanal Gold Mining in Block B, El Callao, Bolívar State, Venezuela in: Dynamics of Mercury Pollution on Regional and Global Scales: Atmospheric Processes, Human
Exposure Around the World, p. 421-450. N. Pirrone &;K. Mahaffey (Eds), July 2005, Springer Publisher, Norwell, MA, USA. Contributors: Marcello M. Veiga, Dario Bermudez, Heloisa Pacheco-Ferreira, Luiz Roberto Martins Pedroso, Aaron J. Gunson, Gilberto Berrios, Ligia Vos, Pablo Huidobro, Monika Roeser. (July, 2005)

Mercury Bioaccumulation by Aquatic Biota in Hydroelectric Reservoirs: Review and Consideration of the Mechanisms:The Guri Case, Bolivar State, Venezuela. Paper presented at the 1st International Forum on Mercury Problems in Hydroelectric Reservoirs, 2001. Authors: Marcello M. Veiga and Jennifer Hinton, Dept. Mining & Mineral Process Engineering, University of British Columbia. (2001)

Advisory Assistance on Avoidance of Mercury Pollution from Artisanal Gold Mining perations in Bolivar State, Venezuela.  Author: Marcello M Veiga. March, 1996.



The southern part of Venezuela, below the Orinoco River, involving State of Bolivar, State of Amazonas and the Federal Territory of Delta Amacuro is called Guayana Region. The main mining activities are conducted in the State of Bolivar which has an area of 240,528 km², comprising 75% of the hydroelectric potential of the country. The number of inhabitants in Venezuela reaches some 24.2 million with a population density of 26.4 persons per km². In 2000, 87% of the population lived in cities and towns with more than 2,500 inhabitants. Less than 5% of the population lived in the Guyana Region. In 1999, the labor force experienced 1.1% decrease in number resulting in an unemployment rate of 13.2% (1,365,752 people). In 2000, 63% of the individuals making up the workforce were men. Unemployment among men reached 12.5%, 1.1% higher than 1999. In 2000, 14.4% of women did not have a job. This was 1.7% higher than in 1999. In the Bolivar State, with a population of 1,214,486, there are about 15,000 people4 directly involved in artisanal and small-scale gold mining. The number of artisanal miners and its gold production has been declined since most artisanal miners working in dredges in the Caroni River have been removed since 2000 and many parts of the river are now flooded by four large hydroelectric reservoirs. Many artisanal miners are now concetrate in km 88 and El Callao, which is a traditional artisanal mining site. El Callao is located in the Northeastern part of the State of Bolivar, 150 km distant from Ciudad Guayana. Gold was discovered in El Callao in 1865 and in 1870 a company was established to produce gold. In 1970, CVG (Government owned company) incorporated a company, Minerven, which nowadays has two cyanidation plants producing together approximately 200 to 300 kg of gold/month: Peru Plant processing 5,200 tonnes of material/month and Caratal plant processing 14,000 tonnes/month. About 15% of the Peru Plant material is Hg-contaminated tailings purchased by the company from the artisanal gold miners.

The area with high concetration of artisanal gold miners in El Callao is known as "Block B" which belongs to CVG-Minerven that rents concessions to small-scale mining individuals/companies. Miners extract the ore from 30-80 m deep shafts using explosives and transport it in small trucks to the Processing Centers (locally known as "molinos") to be crushed, ground, concentrated and amalgamated. Based on the average gold production, the Block B production might be around 1 to 2 tonnes Au/a considering that there are 28 active Processing Centers in the area. In all El Callao, the gold production can reach as much as 5 to 6 tonnes Au/a considering that there are 80 to 90 Processing Centers in all region. By using copper-amalgamating plates to amalgamate the whole ground ore, large amount of mercury is lost with the tailings. The amalgam recovered from the plate is burned on a tray or a shovel. Some millers have good retorts available for miners but the miners insist that the retorting time is too long (15 minutes) and they simply use a propane blowtorch to decompose amalgam, emitting large amount of mercury to the atmosphere and exposing themselves to mercury vapor. This is clearly contaminating everyone directly involved in the ore processing as well as their neighbors, since the Processing Centers are very near the houses. The ratio Hglost: Auproduced is around 1.5 to 2. The mercury emission in Block B is estimated to be between 2 and 4 tonnes/a. In all El Callao, the mercury emission can reach as much as 12 tonnes/a.

The levels of mercury intoxication of the gold miners and millers working in the Block B, El Callao, Venezuela, is one of the most serious in the world. More than 90% of the sampled individuals working in the Processing Centers (millers) have Hg levels in urine above the alert level (5 ?g Hg/g creatinine). . Symptoms typically associated with chronic exposure at very high levels of mercury, acute intoxication, long term exposure at low levels of mercury vapors and long term exposure at high levels of mercury vapors (e.g. muscular tremor) were identified in Block B workers and residents. As a result of indirect exposure of mercury vapors, it was observed that about 27% of the women have Hg concentration in urine above the alert level and 21% above the action level. About 53% of the 62 children sampled have Hg concentration in urine above the alert level and 14.5% above the action level (20 ?g Hg/g creatinine). Almost 10% of the sampled children have levels of mercury in urine above 100 ?g/g creatinine.

It is urgent the introduction of methods to reduce the use of mercury in the gold processing phase, such as gravity concetration, to eliminate the large loss of Hg to the environment due to the use of copper-amalgamating plates. Protection for individuals is also urgent. Different types of retorts must be brought to the miners' attention to reduce occupational exposure and emission of Hg vapor.