Copper mine tailings are discharged to the anoxic zone of the Black Sea at 350m depth, and there is currently consideration of reducing this discharge depth. Oceanographic sampling has provided data allowing calculating whether dilute buoyant plumes will separate from the tailings density current as predicted. Calculations for various discharge rates and slurry dilutions indicate that such plumes will rise similar to 89m above the discharge depth, hence will remain in the deep anoxic zone below the permanent pycnocline at similar to 150m depth at both the present and currently proposed sites. There is some indication from relative seawater density measures that these plumes will drift rather than spreading diffusely. Plume separation from controlled discharges of the tailings slurry was confirmed by visual observations in an experimental tank. The oceanographic sampling also showed that trace element levels in the seawater by the discharge point remained below Turkish marine receiving water quality criteria. (c) 2005 Elsevier Ltd. All rights reserved.