OREAS 628 was prepared from a blend of Zn-Pb-Cu-Ag-Au bearing ores and concentrates from MMG’s Rosebery operation on the west coast of Tasmania, Australia and barren rhyodacite rock sourced from a quarry east of Melbourne, Australia. The key minerals of economic importance include sphalerite, galena, chalcopyrite (minor tetrahedrite) and electrum. Gold occurs as free electrum and also as inclusions within sulphides; silver occurs within tetrahedrite and galena. Pyrite, quartz, silicates, barite, mangano carbonate, pyrrhotite and magnetite form the main gangue minerals (Denwer et al., 2017. Rosebery Cu-Pb-Zn-Ag-Au volcanogenic massive sulfide deposit, in Australian Ore Deposits (ed: G N Phillips), pp 817-821 (The Australian Institute of Mining and Metallurgy; Melbourne). Twenty eight commercial analytical laboratories participated in the characterisation program to certify the elements reported below.
|Analyte||Indicative Value||1SD||Expanded Uncertainty Low||Expanded Uncertainty High||Method|
|Zn, Zinc (wt.%)||1.04||TBD||TBD||TBD||4-Acid Digestion|
|Cu, Copper (wt.%)||1.77||TBD||TBD||TBD||4-Acid Digestion|
|Au, Gold (ppm)||0.870||TBD||TBD||TBD||Pb Fire Assay|
|S, Sulphur (wt.%)||3.40||TBD||TBD||TBD||Infrared Combustion|
|Ag, Silver (ppm)||10.1||TBD||TBD||TBD||Borate / Peroxide Fusion ICP|
|Pb, Lead (wt.%)||0.250||TBD||TBD||TBD||Borate / Peroxide Fusion ICP|
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