|Latitude & Longitude (WGS84):||27° 42' 29'' South , 117° 15' 58'' East|
|Latitude & Longitude (decimal):||-27.70815,117.26629|
|Köppen climate type:||BWh : Hot deserts climate|
An abandoned mine 89 kilometres north-west of Mount Magnet. Contains the North-East Mount Farmer, Main Mount Farmer and South Mount Farmer pegmatites. Small-scale near-surface mining took place during the 1960's on the Main and South pegmatites. This was abandoned in the late 70's. The pegmatites were systematically explored from 1984-1986, trial mining in 1987. Pancontinental Mining Ltd, Cove Mining NL and Richard Read and Associates Pty Ltd formed a joint venture to mine the deposit. Pancontinental dropped out in 1992. In 1995, mining eventually started with the remaining two companies, and Resource Management GP. The quartz hill overlying the pegmatite was removed to gain access to the microlite ore, resulting in a 60 metre diameter by 20 metre deep pit, known as the Main Mount Farmer Pit. Mining ceased in 1999.
The Main Mount Farmer pegmatite is at least 400 metres long, up to 25-35 metres wide, strikes north-east to south-west and dips 30-40 degrees north-west.
Extensive information is known about the pegmatite from D.P. Broomfield's university thesis before mining started. The pegmatite is zoned in layers from the footwall to the hangingwall with:
1. layered aplitic fine grained microcline-quartz-plagioclase pegmatite with muscovite, schorl, almandine and small light green beryl crystals.
2. footwall zone of quartz-microcline-plagioclase pegmatite with muscovite, almandine, schorl and biotite.
3. thin discontinuous zinnwaldite-quartz-albite zone as isolated lens within the wall zone with small green beryl crystals, rare amazonite, faded red spessartine, possibly dark grey-green porcellaneous masses of altered spodumene and euhedral white to bluish topaz with a thick fibrous surficial layer of hydromica being possibly a variety of damourite.(described as spectacular looking by the reference). The zinnwaldite forms curved plates in clusters 3-7cms in diameter.
4. albite-quartz core-margin unit found only on the footwall side of the quartz core, with apatite, bismuth, possibly bismite and bismutite, red and green elbaite, white, grey and rust-stained fluorite, lepidolite, manganotantalite, manganocolumbite, honey-yellow coloured microlite containing plumbomicrolite, green muscovite, possibly the altered spodumene noted above, and altered and unaltered topaz.
5. quartz core of white opaque quartz with clear, white to brown fluorite, and pyrite.
6. thin discontinuous albite-quartz core-margin unit, with fine grained lepidolite, topaz, silver and green muscovite.
7. hangingwall zone of quartz-microcline-plagioclase pegmatite with thin lenses of zinnwaldite-quartz-albite pegmatite within the wall zone.
8. thin fine grained contact zone of quartz-microcline-plagioclase-muscovite.
As commonly noted on Mindat for Western Australia, it is a tragedy specimens were not available for collections before it was mined out.
The reference also described the South pegmatite (but not the North-East). Located 1.25 kilometres south south-west of the Main pit. The pegmatite is at least 200 metres long, 2 metres wide, strikes east south-east and dips 60 degrees north. Most of the pegmatite is said to have been mined out, and the pit partially collapsed. The pegmatite is well zoned but thin, of a blocky grey quartz core, surrounded by a discontinuous thin zone of cleavelandite and quartz containing minor amounts of rubellite, fine grained silver-green muscovite, and lepidolite. Next is an intermediate zone of quartz and microcline, containing large 'books' of muscovite, and roughly crystallised green and white beryl crystals. The wall zone consists of a much finer grained layered aplitic unit of albite, quartz, and mica, with a 2 cm wide band of almandine.
19 valid minerals.
Rock Types Recorded
Select Rock List TypeAlphabetical List Tree Diagram
Entries shown in red are rocks recorded for this region.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
|Neoarchean - Mesoarchean|
2500 - 3200 Ma
|Archean intrusive rocks|
Age: Archean (2500 - 3200 Ma)
Comments: Yilgarn Craton
Lithology: Intrusive igneous rocks
Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. 
2500 - 4000 Ma
|felsic volcanic rocks 74291|
Age: Archean (2500 - 4000 Ma)
Description: Felsic volcanic and volcaniclastic rocks, locally amygdaloidal or fragmental; dacite, quartz-feldspar porphyry, tuff, agglomerate, andesitic lava, quartz-muscovite schist, felsic schist, felsic gneiss
Reference: Raymond, O.L., Liu, S., Gallagher, R., Zhang, W., Highet, L.M. Surface Geology of Australia 1:1 million scale dataset 2012 edition. Commonwealth of Australia (Geoscience Australia).