Follow this video story-telling of how gold is found in alluvial deposits on riverbanks along tributaries of the Amazon.
In the Madre de Dios region of Peru, the rainforest adjacent to the Andes contains one of the most important reserves of biodiversity in the world. This area, however, has been a recent target for gold mining.
After locating gold deposits, miners cut down forests in the area to access the soil. This destroys habitat for rainforest plants and animals, and the runoff from the clearing process flows into rivers and negatively affects aquatic species. After the trees are cut down, miners burn the remnant trees, a process that releases large quantities of carbon dioxide into the atmosphere. Deforestation and the burning of trees is the source of 15% of carbon dioxide emissions worldwide.
In industrial-scale mining operations, heavy equipment is brought in to clear the area completely and move the soil. Dump trucks are filled with dirt from the riverbanks which is then dropped into a large sluice. Hoses are used to filter the soil and separate the tiny gold flecks from the rocks and clay. The sluice acts like a sieve to break up larger pieces of clay. It carries the smallest pieces of soil towards a series of mats where laborers await.
Once the dirt reaches the bottom of the sluice, miners shake it onto specialized mats in order to filter out the tiny gold flecks. The remaining mud is handled by miners and placed into barrels containing mercury and river water. Mercury chemically binds to the gold, and by stirring the mixture, miners can accelerate the binding process. When the gold and mercury congeal into a solid, it is removed and the toxic mercury waste-water is poured back into the river. Over 100 tons of mercury are poured into Amazonian rivers each year. Mercury is known to cause neurological damage to humans, especially children and the elderly, and also harms aquatic species that are sensitive to heavy metals in their environment.
The gold and mercury conglomerate is placed in a small vessel and heated with a blowtorch to burn off the mercury, leaving a purified gold nugget. This process releases harmful mercury vapors into the atmosphere which later enter the food chain during rainstorms. Once the mercury is burned off, a pure gold nugget remains. This is taken to a casa de oro, a gold trading post, where it can be sold at up-to-the-minute prices. The prices of gold have increased exponentially during recent years, which accelerates this process and the destruction of the pristine rainforest.
Areas which were once covered with lush rainforest have been turned into barren and toxic wastelands – all for the price of gold.