Assessment of Geoenvironmental Hazards from Abandoned Mine Workings in the Lead-Zinc District of Abakaliki, South East Nigeria

Abandoned mine workings in the Abakaliki lead-zinc district of Ebonyi State, South East Nigeria, pose a range of geoenvironmental hazards that have received limited systematic characterisation despite their significance for public safety and environmental management. This study assesses the nature, spatial distribution, and severity of geoenvironmental hazards from abandoned mine workings in the Abakaliki district using an integrated field and analytical methodology. Hazard mapping was conducted over a 200-square-kilometre study area using satellite imagery interpretation and systematic field traverses to identify and document abandoned open pits, shafts, adit entrances, and tailings deposits. Geotechnical assessment of pit and shaft collapse risk was conducted using proximity-based indicator criteria. Soil and surface water sampling around abandoned workings was analysed for heavy metal loading. A community survey documented the frequency of human and livestock injury incidents attributable to abandoned mine features. Findings reveal 134 distinct abandoned mine features within the study area, of which 42 are assessed as presenting immediate hazard to communities due to their proximity to footpaths, agricultural areas, or water courses. Surface water heavy metal concentrations downstream of the most active legacy tailings sites exceed WHO drinking water guidelines for lead and cadmium. Children's recreational use of abandoned pit areas is documented in 68 percent of communities. The study produces a georeferenced hazard register and prioritised remediation action plan. Keywords: abandoned mines, geoenvironmental hazards, Abakaliki, lead-zinc, mine safety.