Across sub-Saharan Africa, artisanal and small-scale mining (ASM) – low-tech, labour intensive mineral extraction and processing – now represents a major source of direct and indirect employment for millions of poor people. However, while the livelihood benefits of ASM have been widely documented, most artisanal miners continue to operate in the informal sphere, despite growing interests from governments, donors and policy makers in the formalization of the sector. A substantial literature has emerged around the need for states to formalize artisanal mining, with promises of increased productivity for miners and a corresponding increase in tax revenues for governments. A number of overarching mineral resource policy frameworks, such as the Africa Mining Vision (AMV), have embraced this position, stressing the need for ASM formalization to serve as a platform for poverty reduction and rural development. Focusing on the case of Liberia, this article draws on recent multi-sited qualitative fieldwork carried out in the northwest region of the country, and critically reflects upon the question of why efforts to rollout formalization continue to fail. In doing so, the paper explores the position that the protection of the ongoing informality of artisanal mining is a rational strategy, at least from the perspective of those who profit from it. Addressing the persistence of informality in the sector, the paper argues, should out of necessity first proceed from an understanding of its rationality. Only then will be it be possible to link sustainable mining reforms to broader national and international extractives sector roadmaps, including the AMV.