Golden Kilometre Gold Mine (GK Shoot), Mount Pleasant, Black Flag Goldfield, Kalgoorlie-Boulder Shire, Western Australia, Australiai

Regional Level Types
Golden Kilometre Gold Mine (GK Shoot)	Mine
Mount Pleasant	Mountain
Black Flag Goldfield	Ore Field
Kalgoorlie-Boulder Shire	Shire
Western Australia	State
Australia	Country

Golden Kilometre is a mine in the Mount Pleasant complex, with the Lady Bountiful mine to the north, and to the south a tailings pond storage area and machinery sheds. There are several pits in the immediate area of Golden Kilometre, including one filled in with tailings. The mine produced 2.5 Mt at 4.2 g/t.

The deposit is hosted by the quartz-gabbro Mount Pleasant Sill, basalt, and a shale horizon between the two. Economic mineralisation is largely confined to the quartz-gabbro sill, with minor amounts in adjacent units.

The sill is the most fractured, and Fe rich rock in the Greenstone succession. The greater brittle quartz content has mean't it is more amenable to fracturing, thus allowing gold carrying fluids more access to the rock. Gold mineralisation is controlled by brittle-ductile strike slip faults, associated systems of laminated quartz veins, related altered wall rock, and minor brecciation zones. The major quartz veins are up to 1 metre wide, laminated, with narrow ribbons of pyritized wall rock.

There are three distinct ore shoots called Golden Kilometre, North and North-South. Mineralisation for Golden Kilometre occurs along a main D fault 2 to 6 metres thick. It splays and anastromoses along its length. South and North-South mineralisation is controlled by an oblique fault. South is a major quartz shoot, and has numerous splays of variable orientations, with a wide alteration halo. The highest gold grades is where veins intersect. North-South is a narrow 1 to 2 metre massive to poorly laminated quartz veins and brecciated zones.

Alteration in wall rock shows actinolite-chlorite, replaced by chlorite-albite-biotite-calcite. within a chlorite-calcite distal zone. Intense alteration near the veins is to muscovite-ankerite-pyrite-pyrrhotite-chalcopyrite-sphalerite-arsenopyrite. The muscovite-ankerite zone can be sub-divided into a distal pyrrhotite and proximal pyrite sub-zones.

In the wall rock, gold occurs as discrete particles in gangue and sulphide minerals. Gold occurs in the quartz veins as coarse grains 1-2 mms, with recrystallised quartz, or with sericite, chlorite and ankerite. Gold bearing veins also contain minor galena, sphalerite, pyrrhotite, chalcopyrite and scheelite.

Other Regions, Features and Areas containing this locality

References