Assessing Mining-related risks in the Prestea Huni-Valley Municipality of Ghana

Abstract: The purpose of this study was to assess the risks caused by illegal gold miningactivities (galamsey) in the Prestea Huni-Valley Municipality in Ghana with RemoteSensing and Geographic Information System (GIS) techniques. Satellite imagerytogether with vegetation indices and the Australian Water Observation from Space(WOFS) algorithm was used to identify 3577 cells of potential galamsey sites in thePrestea Huni-Valley municipality. Eight mining risk factors (proximity to galamseysites, rivers, forests, urban areas, static water level, precipitation, erosion, andslope) were considered as important factors to assess galamsey induced risks usingMulticriteria Analysis (MCA) and GISwaps. Analytic Hierarchy Process was used togenerate criteria weights and proximity to galamsey sites obtained the largestweight. Sensitivity Analysis performed showed that the criteria used were robustalthough slope was particularly sensitive. In GISwaps, trade-offs were performed insix steps to cancel out the criteria until one remained. Risk maps obtained from bothmethods were fairly consistent as forest areas, rivers, and urban areas were found tobe in the highest risk zones in MCA and GISwaps. Further investigations must beundertaken to protect human life as well as to protect water and forest resources.