The Black Swan mine extracts disseminated sulphide ores with low nickel grade and high magnesium oxide content.
Black Swan mineralisation comprises of low grade broad bands of disseminated pyrite-millerite sulphides. Silver Swan mineralisation comprises of high grade massive pentlandite-pyrrhotite sulphide lenses:
− The Silver Swan ore bodies either lie on or are adjacent to the steeply east dipping ultramafic footwall contact
− The tenor of massive sulphides is between 10-15% Ni and consistent
Within the Black Swan area the regional felsic Gindalbie formation contains ultramafic units which host numerous massive and disseminated nickel sulphide deposits.
The various lenses which make up the Silver Swan deposit massive sulphide shoots were being exploited from the Silver Swan decline.