Implications of geological knowledge for an effective formalization of artisanal and small-scale gold mining in Numuno district, Mozambique

Artisanal and small-scale gold mining (ASGM) in Mozambique, driven by poverty and lack of employment, contributes to the livelihood diversification in rural areas. One aspect usually overlooked concerning the ASGM is the effective geological characterization of the mining sites. According to local officers, the delimitation of designated areas for ASGM in Mozambique is based on reports of gold discoveries made by rural farmers, rather than a detailed geological study. We described the geological and geographical characteristics of three ASGM sites located in the Namuno district, northeastern Mozambique, based on detailed field survey, and remote sensing. The primary gold ores are associated with quartz veins hosted by amphibolite in the Nanlia and Makorongo sites and quartz-mica gneiss in the Namikupo site. The ores are classified as orogenic gold; such type of deposit may allow for a long-lived gold mining in the same mining site, which favors ASGM formalization. Some ASGM sites in Namuno district are located outside the designated areas and others are within large-scale mining licenses. This discrepancy contributes to an ineffective ASGM formalization in the Namuno district. We think that geological characterization of the mineralization before delimitation of designated areas can foster formalization of the ASGM.