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Seafloor Massive Sulfide (SMS) deposits form on the ocean floor and contain appreciable concentrations of copper, gold, zinc and silver as well as other trace metals. They are the modern-day equivalents of ancient 'land-based' Volcanogenic Massive Sulphide (VMS) deposits such as Kidd Creek in Canada. VMS deposits are currently a major source of the world's copper, zinc, lead, gold and silver.
SMS deposits form on the seaﬂoor and have been found at a wide range of water depths ranging from less than 1 km to more than 4 kms. They form in areas where new ocean crust is forming, such as seaﬂoor spreading centres. Seawater is drawn down through fractures in the oceanic crust, towards a hot buried magma chamber (molten rock body). The heated seawater transforms into a hot acidic hydrothermal ﬂuid and convection causes the ﬂuid to rise up again towards the seaﬂoor. The hot acidic hydrothermal ﬂuid leaches metals from the surrounding rocks during transport, and may also interact with other hot ﬂuids rising from the magma chamber. When these hot acidic ﬂuids carrying dissolved metals and sulphur reach the seaﬂoor (up to 400°C and pH2), they encounter cold ambient seawater (typically 2.6°C, pH8.4 at 1500 m water depth). The sudden change in conditions causes metals and sulphur to precipitate out of solution as metal-rich sulphide, forming an accumulation of sulphide material on the seaﬂoor. SMS deposits commonly carry high concentrations of copper (chalcopyrite) and zinc (sphalerite) in addition to gold and silver.
SMS deposits are typically located in water depths greater than 1,000 meters and in close proximity to tectonic plate boundaries and submarine volcanic activity, mid-ocean spreading ridges, submarine arc volcanic chains , and back-arc basins (such as the Manus Basin in PNG waters).
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The SMS deposits at Solwara 1 and 12 are associated with high grade polymetallic sulphide systems, which are particularly rich in copper and gold. The potential viability of the Project is supported by the high grades of Solwara 1 and 12. Nautilus Minerals’ current resource estimate for Solwara 1 and the maiden inferred resource for the Solwara 12 deposit (located 25km north-west of Solwara 1) can be seen in Table 1 below. For further details refer to the NI 43-101 Technical Report dated March 23, 2012 entitled “Mineral Resource Estimate, Solwara Project, Bismarck Sea, PNG” prepared by Golder Associates Pty Ltd, which can be downloaded from the Canadian Securities Administrators database SEDAR.
*Resource Estimate prepared by Ian Lipton, BSc (Hons), FAus IMM, Principal Geologist, a qualified person as defined by National Instrument 43-101. Effective Date: March 23, 2012. For further details refer to the NI 43-101 Technical Report dated March 23, 2012 entitled “Mineral Resource Estimate, Solwara Project, Bismarck Sea, PNG” prepared by Golder Associates Pty Ltd, which can be downloaded from the Canadian Securities Administrators database SEDAR (www.sedar.com).
Exploration of these zones has presented a challenge to scientists for decades and much still remains to be discovered. However, increased technological advancements are allowing scientists to learn more about the life that exists in this environment. Life in the deep sea must withstand total darkness, extreme cold and great pressure. To learn more about deep-sea marine life, we use sophisticated data collection devices to collect observational, geological and biological samples from the deep.
Remotely Operated Vehicles (ROVs) have been used underwater since the 1950s. ROVs are basically unmanned submarine robots with umbilical cables used to transmit data between the vehicle and researcher for remote operation in areas where diving is constrained by physical hazards. Our ROVs are fitted with video and still cameras as well as mechanical tools for specimen retrieval and measurement. Much of what we learn about the deep sea environment comes as a result of ROV data. To read more on our previous exploration campaigns please click here.