Evaluation of Tin and Columbite Co-occurrence Patterns in the Bisichi Field, Plateau State, North Central Nigeria

The Bisichi field in Plateau State, North Central Nigeria, is a historically productive mining district where tin and columbite occur in spatial association within alluvial and eluvial deposits. This study evaluates the geological controls on tin-columbite co-occurrence and documents current resource distribution patterns in the Bisichi field using updated field investigation methods. Systematic channel sampling and panning tests were conducted across the study area, with samples submitted for cassiterite and columbite-group mineral content determination by heavy liquid separation and X-ray fluorescence. Geological mapping was undertaken to characterise host sediment types and identify feeder pegmatite sources. Results reveal a bimodal distribution of tin and columbite grades, with the highest concentrations found in clay-rich paleo-channel fills at depths of 3 to 8 metres. Columbite ratios relative to tin increase systematically towards the south of the field, suggesting a secondary pegmatite source. These findings have implications for selective artisanal mining strategies and future mechanised extraction feasibility. The study also documents the impact of legacy mining excavations on deposit continuity and provides a revised resource estimate for the northern sector of the field. Recommendations include structured artisanal zoning and cooperative formation to manage extraction more effectively. Keywords: tin, columbite, Bisichi field, Plateau State, alluvial mining.