One of the major problems of non-compliance with environmental standards is the uncontrolled use of mercury, which is still often used for gold mining in artisanal mines. Indeed, in order to extract gold from gold sand, miners often resort to amalgamation, which consists of adding mercury. However, mercury can also be present in gold naturally, and therefore linked to the gold deposit and its geological origin. An elemental chemical analysis does not make it possible to distinguish between mercury added during (anthropogenic) amalgamation and that resulting from a natural geological process.

However, the Minamata Convention, proposed by the UN and ratified in 2017, requires the successive  limitation of anthropogenic releases of mercury into the environment. One of the primary objectives of this convention is to develop strategies to reduce the amount of mercury used in small-scale mining and eliminate it completely in longer terms.

But how can we distinguish between mercury naturally present in gold and that added by amalgamation? We want to provide an innovative solution to this problem. The first results are promising, but we need to optimise our analytical method.

The samples needed for this approach come from the field campaigns detailed in sub-project 3.

Implementation partner : BGI (Better Gold Initiative), Advanced Isotopic Analysis, Hélioparc Pau Pyrénées

Research partner: UNIL

Duration of this sub-project: 6 months, part time

Financial resources required: entirely funded