Tabba Tabba pegmatite (Tabba Tabba Tantalum Mine), East Pilbara Shire, Western Australia, Australiai

Regional Level Types
Tabba Tabba pegmatite (Tabba Tabba Tantalum Mine)	Pegmatite
East Pilbara Shire	Shire
Western Australia	State
Australia	Country

Specimens of well formed white beryl crystals have come from here. It is also the type locality for hexagonal tantalite oxide species simpsonite, discovered in 1934, named after famous Western Australian geologist E.S. Simpson.

The pegmatite is not easily accessed located beyond the station homestead behind a locked gate. The construction of a number of iron ore railway lines to the coast, limits travel east-west along back roads. It could possibly be found by heading a long distance south-west along station tracks from the Strelley pegmatite, but getting lost remains a strong chance. The pegmatite is fifteen kilometres north-east of the station homestead.

Mining at the pegmatites has divided it into a number of sections including the South Workings; the Central, Simpsonite Workings, or Tabba Tabba Tin Mine; the North Workings; the cassiterite bearing pegmatite being a southerly offshoot of the main tantalite pegmatite; the Crawford tantalite prospect the location of which is unclear and has been given as 543 metres from the South Workings or 1.6 kilometres north-west of the Simpsonite Workings, or 1.6 kilometres north north-east of the South Workings; MC 116 north of the North Workings; and Tom Molloy's pegmatite 4.83 kilometres south-west of the Wallareenya Station Homestead.

Alluvial cassiterite was mined from around 1919 to 1928. E.S. Simpson visited the location in 1927 and noted cassiterite mining on Allan Crawford's pegmatite by Consolidated Mines Selection Company, and further mining elsewhere on the pegmatite by Thelemann and Young/Moulden for Tantalite Ltd. The last two licences merged in 1933, and mining continued until early 1943. The leases were then taken over by the Commonwealth Government as part of its war-time effort, but no mining took place. After the war the leases were returned to Tantalite Ltd, but they had run out of funds so sold it to Northwest Tantalum Ltd but again no mining took place, and the lease was relinquished in 1957. Ownership passed to J.A. Johnson and Sons around 1960, Avela Pty Ltd 1967, Goldrim Mining 1968. No mining took place through this entire period. In 1998, alluvial tantalite and cassiterite was gathered by tribute miners for Sons of Gwalia.

The Tabba Tabba pegmatites have intruded into a narrow north-east to south-west trending belt of metamorphosed gabbro sandwiched into metamorphosed Warrawoona Group sediments.

The Main tantalite pegmatite is 610 metres long and 15-55 metres wide, and dips steeply to the north-east. The pegmatites contains several quartz cores; around the cores is a thin zone of abundant white euhedral beryl that projects into the quartz; outside this a unit of mostly mined out fine grained mixed albite, tantalite, simpsonite and a greenish granular muscovite; then a layer fine grained to coarse grained albite-muscovite-quartz with spessartine, the last 3 layers reaching a maximum total width of 107 centimetres. External to this is an intermediate zone of quartz-microcline-plagioclase-muscovite; and a wall zone of microcline-quartz-plagioclase.

Species found at the Main pegmatite and its cassiterite rich southerly offshoot are albite, white tabular doubly terminated beryl crystals, cassiterite, lithian muscovite, magnetite, microcline, microlite, ball muscovite, quartz, simpsonite up to 1cm, spessartine and tantalite.

The Crawford prospect pegmatite intrudes into amphibolite, and is 31 metres long by 4.6 metres wide, dipping 45 degrees to the east. The hanging wall is quartz and the footwall is weathered albite-muscovite-quartz with spessartine, magnetite, tantalite, microlite and cassiterite.

In 2015, Pilbara Minerals Limited decide to mine the site constructing a processing plant with a large pit planned. Considering it is type locality status for simpsonite, named after a locally famous government geologist, and has seen fine white beryl specimens and other species, this location is a prime candidate for a mineral heritage law, which bans further destructive large scale mining. It is ironic that historic mining methods allowed us to gain access to its treasures, while modern methods completely destroy it. More annoying, is Pilbara Minerals a year later after flattening the site state they are having problems with the processing plant, and are suspending operations. In 2017 the plant is sold, and removed to Mount Mulgine elsewhere in the state, meaning the destruction of the pegmatite had been completely pointless. The pictures on Mindat by Sue and Gert represent some of the last people to visit the location before it was altered.

Geochronology

Mineralization age: Mesoarchean : 2974 ± 59 Ma to 2877 ± 20 Ma

Important note: This table is based only on rock and mineral ages recorded on mindat.org for this locality and is not necessarily a complete representation of the geochronology, but does give an indication of possible mineralization events relevant to this locality. As more age information is added this table may expand in the future. A break in the table simply indicates a lack of data entered here, not necessarily a break in the geologic sequence. Grey background entries are from different, related, localities.

Geologic Time				Rocks, Minerals and Events
Precambrian
	Archean
		Mesoarchean		ⓘ Cassiterite (youngest age) 2877 ± 20 Ma ⓘ Cassiterite (oldest age) 2974 ± 59 Ma

Other Regions, Features and Areas containing this locality

References