Mount Farmer Mine (Niobe prospect), Yalgoo Shire, Western Australia, Australiai

Regional Level Types
Mount Farmer Mine (Niobe prospect)	Mine
Yalgoo Shire	Shire
Western Australia	State
Australia	Country

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.

Other Regions, Features and Areas containing this locality

References