Geological Behavior (GBR)

This study presents an integrated geophysical-geotechnical assessment of sand resources in Nung Ikono Ufok, Nigeria, to evaluate their suitability for large-scale dredging operations. Combining Electrical Resistivity Tomography (ERT) with borehole sampling and laboratory analysis, we characterized subsurface sand deposits, identified constraints, and developed a Dredging Suitability Index (DSI) to guide extraction. Key findings reveal 32,000 m³ of high-quality, well-graded sand (USCS: SW) within 15 m depth, meeting ASTM C33 standards for construction. ERT delineated sand bodies (150–500 Ωm) with over 85% accuracy compared to borehole data, though discontinuous clay layers and saline intrusions reduced recoverable volumes by 15–20% locally. The integration of geophysical and geotechnical data reduced exploration costs by 40% by minimizing unnecessary drilling. The paper recommends prioritizing extraction in zones with DSI >0.7 (e.g., near BH1–BH2), employing real-time resistivity monitoring to avoid clay/saline contamination, and implementing environmental safeguards to mitigate turbidity and coastal erosion. This work provides a replicable model for sustainable sand resource assessment in deltaic regions, balancing economic viability with geological and ecological constraints.