Structural controls of the expansion of small‐scale artisanal gold of Bouda area (Kaya‐Goren greenstone belt, Burkina Faso) from remote sensing

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Résumé

Small‐scale artisanal mining is a vital sector of the economy of Burkina Faso. This activity, correctly regulated, remains essential for the population, despite security issues since 2015. Exploration of new areas for gold mining in this condition is difficult but essential to continue extractive activities. It is, therefore, important to define exploration corridors, with science‐based evidence for good prospects, to support artisanal miners in a way that minimizes the environmental impact.
We describe a remote sensing approach applied to define future mining corridors in the Bouda site, whereas environmental impacts are minimized. The remote sensing approach reveals the structural control of expanding small‐scale artisanal gold activity. In detail, the Minimum Noise Fraction (MNF) is applied to Landsat images (7‐ETM+, 5‐TM, and 8‐OLI, respectively, for 2000, 2011, and 2022) to detect extraction sites and perform a spatiotemporal analysis of the expansion of areas affected by gold extraction. The near‐infrared and mid‐infrared bands of Landsat images significantly contribute to the detection of extraction areas.
In addition, a lineament analysis of the site is achieved using Principal Component Analysis (PCA) applied to Landsat 8‐OLI. The correlation between gold occurrences and high lineament densities, especially in the dominant NE‐SW direction, demonstrates the structural control of the expansion of the mining activities. Five new potential prospecting corridors are proposed at the Bouda site.

Mots-clés

Artisanal mining, Landsat, Remote sensing