Life Cycle Inventories of Different Types of Gold Extraction from Small-Scale Mining in the Amazonian Rainforest in Brazil

by Benjamin Fritz (presenting author)1, Bernhard G. Peregovich2, Mario Schmidt1

1: Institute for Industrial Ecology, Pforzheim University, Germany; 2: Federal University of Western Pará, Santarém, Brazil

 

In the 80’s the discovery of a gold nugget moved thousands of courageous gold prospectors, called Garimpeiros from all over the world to the remote Amazon rainforest to gain wealth. This historic event known as Serra Pelada symbolizes how gold, like hardly any other material has formed and destroyed civilizations, triggers emotions and is a symbol of wealth and success. But gold comes at a price, not only financially. It creates negative impacts that are of great importance – resource depletion, extensive use of chemicals, toxic emissions, high energy consumption as well as social concerns just to name a few. Today gold is still extracted in the Amazonian rainforest with artisanal small scale mining (ASM), small operations of 1-5 people with very rudimentary tools, called Garimpos. In this study primary data regarding the use of resources (e.g. fuel, land or mercury) of gold from ASM was gathered in the Tapajós Region in Brazil. It was possible to collect data on various types of gold extraction methods including alluvial mining with hoses and sluice boxes (hydraulic mining), underground mining with and without cyanidation and dredges. As an exemplary excerpt for one area, the evaluation of gathered data from seven hydraulic mining Garimpos show that an average ten days per operation yields around 0.4 kg of gold. This results in 6400 kg diesel and 0.66 kg mercury for a functional unit of 1 kg gold. One well-established method to analyze environmental impacts of products is Life Cycle Assessment (LCA). In LCA databases as of today there is no data on ASM. Several similar studies (Cenia et al., 2018; Kahhat et al., 2019) have been conducted in other countries since the first study by Valdivia has been published in 2011. We hope this data lack can be closed by studies like this.