Title: Deleterious Elements Associated with Submarine Hydrothermal Deposits in Manus Basin, Papua New Guinea
Abstract:The Manus back arc basin is well known for hosting submarine hydrothermal deposits of Vienna Wood, Pacmanus, Onsen site and Solwara 1-12. The Vienna Wood located in the Central Manus basin is a typica...The Manus back arc basin is well known for hosting submarine hydrothermal deposits of Vienna Wood, Pacmanus, Onsen site and Solwara 1-12. The Vienna Wood located in the Central Manus basin is a typical Cu-Zn type of mineralization hosted by mid-oceanic ridge basalt and consists predominantly of sphalerite, wurtzite, chalcopyrite and gangue minerals of anhydrite, gypsum and silica. In contrast, the Pacmanus hydrothermal deposit in the eastern part of the Manus basin is hosted by rocks ranging from basalt to dacite and rhyodacite. The mineralization is of the polymetallic Zn-Cu-Pb-Au type consists of ore minerals of sphalerite, chalcopyrite, bornite, wurtzite, pyrite, marcasite, enargite, tennantite, galena, Pb-As-Sulphosalt, gold, covellite, digenite, chalcocite and gangue minerals of barite, amorphous silica, anhydrite and gypsum. The chemical composition of sphalerite, galena, gold and tennantite-tetrahedrite indicate high concentrations of Lead, Arsenic, Silver, Iron, Copper and Antimony compared to their stoichiometric composition. The Onsen site in the Eastern Manus Basin is the first deep sea acid sulfate type of mineralisation and consist of enargite, covellite, chalcopyrite, pyrite, marcasite and gangue minerals of pyrophyllite, alunite, quartz, cristoballite, amorphous silica and native sulfur. The PNG Government has granted exploration and mining licenses to Nautilus Mineral for commercial exploitation of these deposits and Solwara 1 deposit in the Eastern Manus Basin. Nautilus minerals has done extensive exploration and reports indicated and inferred a mineral resource of 1030 kt and 1540 kt respectively for their Solwara 1 project east of Pacmanus site at a 2.6% Cu equivalent cut off grade. Whether this mineral resource is sufficient to deliver PNG first deep sea mining or not will depend on the success of the trial mining method that is currently being developed. Studies done on nearby Pacmanus and Onsen submarine hydrothermal deposits indicate that the deposits contain a much higher proposition of deleterious elements such As, Pb and Sb. Nautilus did not disclose the full mineralogy and assay results of the Solwara 1 and 2 projects to the public domain apart from Cu, Au, Ag and Zn. Nautilus did not suggest how it will address toxic and heavy metals that are associated with the ore concentrate in its Environmental Impact Studies.Read More
Publication Year: 2013
Publication Date: 2013-01-01
Language: en
Type: article
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Cited By Count: 2
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