Remote Sensing Detection of Illegal Mining Sites in Zamfara State

Artisanal and small-scale gold mining in Zamfara State has expanded dramatically over the last decade, causing severe land degradation, water contamination, and public health risks. This study detects and maps illegal mining sites in the Maru and Anka LGAs using multi-temporal Sentinel-2 imagery from 2018 to 2023. Bare soil and disturbed land indices including the Normalised Difference Bare Soil Index and the Iron Oxide Ratio are computed to highlight freshly excavated mining pits and spoil heaps. Change detection analysis identifies new mining activity that has expanded the total disturbed land area by approximately 22 percent over the study period. Spectral analysis of tailings ponds reveals elevated iron and sediment concentrations consistent with mercury amalgamation discharge. Results are validated using high-resolution PlanetScope imagery and field verification reports. The study recommends deploying a satellite-based monitoring system to support the Mining Cadastre Office and Zamfara State government in enforcing artisanal mining regulations. Keywords: illegal mining, remote sensing, Zamfara, land disturbance, Sentinel-2