Fischer Shoots (Fisher complex), Kambalda Nickel mines, Kambalda, Coolgardie Shire, Western Australia, Australiai

Regional Level Types
Fischer Shoots (Fisher complex)	- not defined -
Kambalda Nickel mines	Group of Mines
Kambalda	Town
Coolgardie Shire	Shire
Western Australia	State
Australia	Country

Located immediately west of the Kambalda East town-site. A gossan was found at Tripod Hill in 1965. Mined 1972-1977, and resumed 1979. The deposit is the most structurally complex in the Kambalda area.

The komatiite flow in this area is 25-200 metres thick. The footwall is metabasalt-ultramafic-sulphidic metasediments. The ultramafic host is talc-magnesite chlorite rock, or antigorite serpentine, with varying amounts of talc, and porphyroblastic carbonate with chloritic margins.

The deposit is part of the north-south trending Fisher Syncline, intensely faulted, and plunging gently south. The ore belt is 1400 metres long, trending north north-west. It contains a large number of small sub-shoots, some mentioned as follows.

The best mineralisation in the southern part of the deposit is in F Zone, overlain by matrix to disseminated ore. Deformation has formed irregular layers and lenses of massive ore, reaction zone breccia ore, and matrix ore, intruded by porphyry sills parallel to the ore, and dykes commonly truncated where it meets the ore. The ore zone is 1.5 to 7 metres thick of matrix to disseminated ore, underlain by thin irregular massive and stringer sulphides.

What is known as the 70 sub-shoot is layered massive ore, with abundant fine grained pyrite lenses at the faulted margins with the metabasalt boundary on both sides. Porphyry dykes truncate the ore in one section.

H Zone shows as persistent thin basal layer of massive ore. B and G Zone contact ore, small and patchy.

Hanging Wall ores is blebby sulphides within the ultramafic units, called B Zone Hanging Wall, and 63H. The first is a complex folded south plunging horizon of blebby, disseminated, matrix, supergene, and transitional sulphides. 63H is an irregular zone of blebby milleritic sulphides, with patchy disseminated ore, and sulphide stringers.

The 62H sub-shoot is parallel to the F Zone contact, consisting of strongly foliated disseminated ore, and stringer sulphides, abutting pyrrhotitic metasediments in the southern part.

12H and 13H cut numerous small faults across 150 metres. Some massive ore is found in the northern portion of 12H, injected into the top of a pile of underlying spinifex textured metapicrite. The southern portion of 13H is low grade blebby and disseminated ore abutting sulphidic metasediment.

15H Hanging Wall ore, west of the Fisher Thrust, is massive, matrix, and disseminated sulphides, Ni values gradually decreasing as the sulphides grade into barren ultramafic rocks. The Footwall is spinifex textured metapicrite.

14H and 16H sub-shoots shows mineralisation in inclined synclinal folds. The ore body dips 30-60 degrees east. It is disseminated ore, overlying spinifex textured ultramafic Footwall rock, with cherty sulphidic pyrrhotitic and chloritic metasediment to the north. The deposit shows complex folding with lenses of pyrrhotite rich massive ore, in peridotitic to picritic ultramafic rocks in the core of the syncline.

Overall primary mineralisation is pyrrhotite, pentlandite, pyrite, chalcopyrite, magnetite, chromite, millerite. Hanging Wall ore contains blebby magnetite. Supergene violarite and pyrite down to 40 metres below the surface in disseminated ore, 60 metres in massive ore. Violarite is contained in a transition zone down to 120 metres, and 150 metres in D Zone.

F Zone ore as an example shows Ni grades as contact ore 8-11% Ni, matrix ore 4-6% Ni, and pyrrhotite rich massive ore in 14H 3-7% Ni.

Other Regions, Features and Areas containing this locality

References