Distribution, mineralogy, and geochemistry of gold and silver in the north end orebody, Rosebery, Tasmania

Study of the spatial and mineralogical distribution of gold and silver in the Rosebery north end orebody indicates that both silver and gold are concentrated in massive sphalerite-galena-pyrite ore and barite mineralization. Six styles of gold mineralization have been recognized: 1) in massive sphalerite-galena-pyrite ore (the dominant occurrence); 2) in massive barite mineralization; 3) in the upper parts of pyrite-chalcopyrite pods; 4) in distal pyrite mineralization; 5) in footwall mineralization; and 6) in remobilized quartz-carbonate veins. Mineralogically, gold occurs as electrum. The grain size of electrum has a lognormal distribution, with most grains having dimensions of less than 25 μm. Silver occurs dominantly in tetrahedrite, and to a lesser extent, in galena. -from Authors