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article · Applied Earth Science Transactions of the Institutions of Mining and Metallurgy

Gold mineral prospectivity mapping using gradient boosting machine and decision tree models in northwestern Ghana's Danyour Area

In plain language

Gold mineral prospectivity mapping was carried out in the Danyour Area of north-western Ghana using gradient boosting machine and decision tree algorithms. By integrating seven geo-thematic layers derived from airborne magnetic, radiometric, and geochemical surveys across 218 labelled locations, the models captured non-linear relationships governing gold mineralisation. Analysis highlighted arsenic concentration, potassium to equivalent thorium ratios, equivalent uranium to equivalent thorium ratios, and lineament density as the primary predictors of gold localisation. The gradient boosting model outperformed the decision tree classifier, achieving an area under the curve of 0.87 and a mean average precision of 0.916. The models classified between 31.54 percent and 36.96 percent of the territory as prospective. These validated spatial outputs identify credible exploration targets to improve resource planning and mitigate the environmental damage linked to unregulated artisanal mining.

Key takeaways

  • Gradient boosting machine and decision tree algorithms effectively delineated gold prospectivity zones using seven geophysical and geochemical data layers.
  • The gradient boosting model demonstrated superior performance, achieving an area under the curve of 0.87 and a mean average precision of 0.916.
  • Arsenic concentration, lineament density, and specific radiometric ratios were identified as the most influential predictors of gold presence.
  • The models classified between 31.54 percent and 36.96 percent of the Danyour Area as prospective for gold.

Why it matters

Illegal artisanal gold mining causes severe land degradation and pollutes critical water bodies in Ghana. Applying multi-variate machine learning to regional geophysical and geochemical data enables precise identification of prospective zones. This improves exploration efficiency, assists authorities with formal land-use planning, and reduces the environmental and water-resource damage associated with unregulated, unguided prospecting.

Commercialisation angle

This work represents an applied and tested spatial-modelling approach relevant to commercial mineral exploration companies, geological surveys, and land-use regulators. By generating validated prospectivity targets, the tools can help reduce commercial exploration risk and survey expenditure. The application appears ready for immediate use by technical teams to guide targeted field exploration programmes and support the formal allocation of mining concessions.

AI-generated from the published abstract. Always read the original work before citing.

Abstract

Gold mineral prospectivity modelling was carried out over the Danyour Area of northwestern Ghana using gradient boosting machine (GBM) and decision tree (DT) machine learning classifiers. The study responds to the escalating environmental burden of illegal artisanal mining, locally known as galamsey, whose degradation of land and water resources underscores the need for responsible, well-targeted and sustainable mineral exploration. Although earlier prospectivity mapping in the area relied on bivariate data-driven techniques that appraise each predictor independently, this study advances that work by applying multi-variate machine learning classifiers capable of resolving the non-linear interactions among geoscientific predictors that govern gold localisation. Seven geo-thematic layers derived from airborne magnetic, radiometric and geochemical datasets were integrated through the GBM and DT algorithms and trained on 218 labelled points (109 gold and 109 gold-sterile occurrences) to generate prospectivity maps for the study area. Feature-importance analysis identified arsenic concentration, the K/eTh ratio, the eU/eTh ratio and lineament density as the most influential layers, a ranking consistent with the depositional and hydrothermal processes associated with gold mineralisation in the area. Comparison of the two classifiers showed the GBM-based map to outperform the DT-based map on both discrimination and precision metrics, returning an area under the curve of 0.87 and a mean average precision of 0.916, against 0.84 and 0.806, respectively, for the DT model. Classification metrics for both models exceeded 0.7, confirming their reliability in delineating gold prospects, with 31.54% and 36.96% of the study area classified as prospective by the GBM and DT models, respectively. The predicted high-potential zones corroborate geologically favourable provinces of gold occurrence, validating the robustness of the models. These outputs provide credible exploration targets that can support land-use planning while minimising the exploration risk and the environmental and water-resource impacts associated with unregulated mining.

Research topics

  • Geochemistry and Geologic Mapping
  • Mining and Resource Management
  • Mineral Processing and Grinding

Read the original research

This page summarises published work. The authoritative version sits with the publisher.

DOI: 10.1177/25726838261480241

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