Hunt Shoot, Kambalda Nickel mines, Kambalda, Coolgardie Shire, Western Australia, Australiai

Regional Level Types
Hunt Shoot	- not defined -
Kambalda Nickel mines	Group of Mines
Kambalda	Town
Coolgardie Shire	Shire
Western Australia	State
Australia	Country

Ni sulphides. South of the Lunnon shoot, near western shores of Lake Lefroy. No outcrop. Discovered 1970. Largely mined out 1974-1977. Structurally complex.

The komatiite flow in this area is 25 to 100 metres thick. Ultramafic host is massive talc-magnesite chlorite rock, with a small area of antigorite. The footwall is chloritic-biotitic metabasalt, with 1 metre thick contact ore. Quartz veins are common, but truncated at the contact with the overlying ore or ultramafic rock. A thick sill like porphyry intrudes the upper area, thinning abruptly to the west where it overlies the contact ore. Vertical to moderately south-west dipping reverse faults disrupt the footwall contact.

The deposit is 900 metres long, up to 300 metres wide. A small trough like structure is found in the central part of the deposit. Margins of the deposit are bounded by the Q Fault and Harry Fault. One third volume of ore is hanging wall ore.

There are a large number of sub-shoots, including named as D Zone, Q Fault, D Zone Deeps, Harry Fault, F Zone, A Zone, E Zone. The highest grade ore is found in A and D, 2 to 3 metres thick of matrix and massive ore, layered vertically, with variable thickness and distribution, with also quartz veins. Also found is breccia ore in a reaction zone, and disseminated ore, also with highly variable thickness.

The Q Fault sub-shoot has a complex history, the source mentioning structural features such as normal faults, some reverse movement, slickensides plunging 15 degrees south south-east, and sinistral oblique strike slip movement, all influencing its appearance.

D Zone is in the southern part of the deposit in a shear zone, sub-parallel to, and 5 to 20 metres above the Footwall contact.

F Zone is structurally related to D Zone Deeps, with mineralisation in a corridor 80 metres wide, with a structurally disturbed contact, ore less than one metre thick. The ore is massive-breccia layers, and matrix-disseminated ore interleaved with barren and sub-grade material.

The large E Zone contains two Hanging Wall shoots called Main and the smaller East. This is further divided into West, Central and East sections. High grade ore is in Central. Most of the E Zone is poorly layered massive ore, overlain by matrix to disseminated ore 0.5-2.5 metres thick. The top and bottom contacts are spinel rich. Coarse grained pyrite crystals are found throughout the ore, the crystals(some cubic) sizes varying from layer to layer.

Primary ore is pyrrhotite, pentlandite, pyrite, chalcopyrite, magnetite, and chromite. Pentlandite has been partly altered to violarite in most of the Hanging Wall ore. Locally melonite is associated with pyrite, chalcopyrite and gold in quartz veins in the Footwall metabasalt contact zone in the D Zone. Massive ore contains strongly foliated pyrrhotite aggregates, with kink bands and deformations twins. Also pentlandite aggregates, and some chalcopyrite. Pyrite is the main sulphide mineral in Hanging Wall ore, with sub-ordinate pyrrhotite, pentlandite and chalcopyrite.

Contact ore grades at 10% Ni, Hanging Wall ore 11-12% Ni, Matrix ore 6-7% Ni, Disseminated ore 2-4% Ni.

Other Regions, Features and Areas containing this locality

References