Characterization and environmental impact assessment of gold mine tailings in arid regions: A case study of Barramiya gold mine area, Eastern Desert, Egypt

摘要

Geochemical and mineralogical characterization and environmental impact assessment were performed on Barramiya gold mine tailings, Eastern Desert, Egypt. The Barramiya gold mine is situated within ophiolitede-corated Nugrus suture zone, which composed of dismembered sequence of highly deformed and metamorphosed mafic to ultramafic rocks and their hydrothermal alteration products (carbonate rocks), interbedded with meta-volcano clastic rocks of the Nubian Shield. Morphometric parameters were quantified using ArcGIS 10.0 with Shuttle Radar Topography Mission (SRTM) maps. A total of four tailings samples were gathered and analysed by XRF, XRD, ICP-OES/MS and ESEM. Tailings are characterized by homogeneous silty fine sand, high carbonates in the form of dolomite and ankerite, and low sulfides content in the form of arsenopyrite and pyrite relics. High concentration averages of heavy elements are found for As (2936 mg/kg), Cr (237 mg/kg), Sr (219 mg/kg), Ni (150 mg/kg), V (131 mg/kg), Zn (64 mg/kg), Cu (51 mg/kg), Co (19 mg/kg) and Pb (12 mg/kg). They reflect mafic and ultramafic rocks, graphite schists, and quartz veins of the study area. Gypsum is present as secondary phase, identified in the shrinkage crack fillings. Morphometric drainage basin parameters for wadi Barramiya basin show rectangular to subdendritic drainage pattern with a moderate hazard degree. This study recommends designing multiple-layered dry cover, overlain by plant cover at uppermost part for treatment of the gold mine tailings; otherwise, wind and water erosion can easily remove all dissolved and unconsolidated material that absorb heavy elements and would create a potential risk to the surrounding ecosystem.