Gold mining and mercury – a time bomb in Amazon
The greatest threat to the environment associated with artisanal gold mining in Amazon is the use of mercury to amalgamate the gold (photo at left). Both metallic mercury discharged into the rivers by the washing process, and the mercury vaporized during combustion of the amalgam in order to separate the gold, are very dangerous to health. This is a time bomb which will explode sooner or later. At the end of the extracting process, lakes of polluted mud and large areas of cleared land are abandoned in the forest, leading to desertification of entire regions.
Mercury is a neuro-toxin, It affects the cerebellum, which is the part of the brain that helps one move properly, and co-ordinate the movements. Mercury also harms the kidneys and other organs, but the neurological damage it does is irreversible.
The story presented here shows what is known as “garimpo”(1), namely the most rudimentary form of mining (more info below). It may take place in the open air or in galleries dug out deep into the rock (previous photo). It is a story about bulldozzers carving out pits in the middle of the rain forest and about orphan diseases, such as malaria and leishmaniosis – the pharmaceutical industry is not generally interested in developing new drugs to combat them because they are only prevalent in poor regions.
It is also a story on adventurers dreaming of becoming rich overnight. A vague rumour heard on the grapevine can transform an uninhabited and remote place into a bustling village in the space of a few weeks. We followed the trail of one of these rumours and end up reaching in the Agua Branca (White Water) region, in the south-west of the State of Para. We also worked at the Yanomami Indigenous territory in Roraima State invaded by gold miners. Both in the Brazilian Amazon.
(1) Garimpo – Gold-washing techiniques used in Amazon region: chupadeira and hard rock mining.
Chupadeira is a hydraulic extraction technique. Firs of all, heavy machinery is used to excavate the site where the search for gold is taking place, in order to reach the gold-bearing sediments. Next, the prospectors direct high-pressure water jets into these large, deep holes to dislodge and break up the sediments. The washing process is followed by what is called “despescagem”, removal of the material collected in the sluice box. The largest gold particles are separated simply by gravity, in the case of the smallest particles, mercury is used to amalgamate the metal, concentrating the specks of gold dispersed in the sediment (photo at left). The garimpeiros then use a butane torch to vaporise the residual mercury, leaving a concetration of gold particles at the botton of the pan. No precautions are taken to prevent the mercury pouring into the river, coming into contact with the skin, or to protect against the inhalation of toxic vapors. After an area is exhausted, the process is repeated in another location, scarring the world´s greatest tropical forest with deserts of white sand and lakes of blackish water and mud.
In hard rock mining (previous photo), the extraction procedure begins differently: following examination of the outcrops and identification of the seams, pits are dug out or precarious and dangerous tunnels are excavated (underground mining). The ore is then crushed, after which the gold is separated as indicated above – first by gravity and the by amalgamation.