Metalliferous sub-marine sediments of the Atlantis-II-Deep, Red Sea

CIM Bulletin, Vol. 81, No. 910, 1988

MEHMET GUNEY and MUHAMMAD A. AL-MARHOUN, K.F. University of Petroleum and Minerals, Dhahran, Saudi Arabia, and ZUHAIR A. NAWAB Red Sea Commission Jeddah, Saudi Arabia

The Atlantis-II-Deep is a stratified metalliferous deposit located along the median valley of the Red Sea at a "water depth of about 2200m. The metal-bearing mud contains sulphides of zinc, copper and iron with significant amounts of silver, gold and cobalt. A variety of oxide, siliceous and carbonaceous gangue material is also present. Long sediment cores indicate that the thickness of the deposit may reach 25 m, but the average kriged thickness of metal-rich sediments is about 11 m. Mining geostatistics was applied to estimate the Red Sea offshore mineral resources. Experimental semi-variograms were computed along 0 ± 180 degrees and then models were fitted to analyze the mineralization phenomenon. Kriging estimates indicate that 696.330 million t of bulk sediments contain 1.891 million t of zinc, 0.425 million t of copper and 3.75 thousand t of silver. Gold and cobalt contents were calculated from the analysis of solids in flotation concentrates as 47 t and 5368 t respectively. The significant outcome of implementing geostatistics to the Red Sea brine precipitates is not only for the evaluation of metal resources, but it also provides a useful tool in the optimization of selective dredging of appropriate areas to be mined.

Keywords: Geostatistics, Atlantis-II-Deep, Red Sea, Mineral resources, Sedimentary deposits, Ore reserve estimation, Exploration, Offshore mining.