Alluvial mining and underground mining in the ASM

September 01, 2018
Alluvial mining and underground mining in the ASM

By Franco Arista Rivera | Gold Programme Manager in Solidaridad Network

The alluvial gold mining is an economic activity that takes advantage of the detrital gold deposited in terraces, pleasures, plains, rivers, etc. This geological condition allows artisanal miners to obtain gold material more easily, using rudimentary technology and low-skilled labor.

For its part, underground gold mining is an economic activity that involves the use of gold veins or seams that are located in the subsoil, which are difficult to access and require more investment. However, artisanal miners carry out this activity in conditions of risk to health and the environment, with limited technical assistance and lack of financing.

During the last meeting of the Gold Solidarity Program, I consulted with my colleagues about the percentage participation of both alluvial mining and underground mining in the countries where we have been working with the program.

The result was the following:

The results indicate that in Bolivia, Colombia and Ghana alluvial mining predominates in front of underground mining, which concentrates a large number of people working in tropical zones, being secondary deposits are easy to process when washed with water, subsequently amalgamated and reforested. In the cases of Peru, Tanzania, Uganda and Kenya, topographic and geological conditions predominate primary deposits, forcing underground mining to access the resource with empirical exploitation techniques and where the processing of the mineral with mercury predominates.

According to geologist Rafal Swiecki, alluvial mining requires less investment to get it going and operational costs are lower than underground mining. He also concludes that exploring an alluvial deposit costs less than exploring a primary reservoir.

Finally, when designing formalization programs for small-scale miners, it is essential to know the socioeconomic context, the methods of exploitation and processing, as well as the marketing chains, so that such policies are coherent with the reality of the miner and accelerate the shift towards responsible mining of ASM.