Thanks to the missions carried out within Wanamei project, we have been able to analyze the methods and devices used by artisanal miners for gold extraction.
In this region, alluvial gold is present as very little flakes of a size between 40 and 450 microns. Thus, extracting alluvial gold means to extract those tiny flakes from auriferous sand.
For this purpose, miners use several processes and devices.
The first method consists on suctioning the auriferous material using three different options:
- The chupadera: This device erodes land with a water-hose. Auriferous material is then suctioned out with a suction tube.
- The traca: This floating device is placed on the flooded lands. The aspiration tube is planted in the ground and suctions the immersed auriferous material.
- The caranchera: This floating device is placed on the river sides. The aspiration tube is planted in the ground and suctions the immersed auriferous material.
The second method of extraction is semi-industrial and consists in using heavy mechanical machines in order to load dry auriferous material (excavator, front loader, etc.).
These methods of extraction are both dangerous for the operators:
- The obstruction of the suction tube forces the operator to regularly dive under water in order to take off blocking rocks. He is constantly immersed into extremely dirty and polluted water.
- High risks of landslides and mudslides
- High noise pollution (use of old truck motors, etc.)
These methods are also harmful for the environment:
- Cut and uprooted trees
- Massive areas of extraction due to the impossibility to extract deeply
- Soil and water pollution
- Creation of groundwater tables
- Lack of land rehabilitation and reforestation on mining zones
The cost of these machines is not only expensive when miners purchase it but also when they have to repair a breakdown and cannot fix it on the spot.
That is why Wanamei project and working groups mobilized their efforts to improve excavation techniques and design a new device, improving or substituting current suction systems.
Our first idea consisted in designing a new digging head, able extract more deeply the gold material. However, this solution has not been validated during our trials made on the spot with the miners.
Considering a contextual dynamic, the project team proposed to work on a polyvalent mini-excavator, able to extract material, carry it to the cleaning ramp (tolva) and clean the mine site before and after gold-operations (reforestation and waste rocks restoration). Miners validated this modular concept, giving them the opportunity to extract gold and to rehabilitate mine sites.
This global concept, called “the Boa” referring to local myths, is part of our strategy with the intention of improving local mining practices, reducing the burden of work and minimizing environmental impacts in Peruvian Amazon.