Kempton Brothers Beryl Mine, Yinnietharra, Upper Gascoyne Shire, Western Australia, Australiai

Regional Level Types
Kempton Brothers Beryl Mine	Mine (Inactive)
Yinnietharra	Station (farming)
Upper Gascoyne Shire	Shire
Western Australia	State
Australia	Country

Pegmatite located 6.7 km south of Pyramid Hill on Yinnietharra Station, Western Australia. It is the type locality of clinobisvanite.
The pegmatite was worked for beryl. It intrudes a quartzite belonging to the lower Proterozoic Wyloogroup (Bridge & Pryce, 1974).

Note 1: The Yinnietharra area is known for many pegmatites which were exploited for beryl during and after World War II.
Note 2: This is not the famous dravite locality (which is not a pegmatite), see Soklich Open Pit Mine, Yinnietharra.

This pegmatite has historically been called several names including the Arthur River South pegmatite (Trautman 1992), Tobin Well pegmatite (Johnston et al 1990), Marloo No2 pegmatite (Richards 1999), Marloo Well No2 pegmatite (Fetherston 2004). Mindat once listed the location incorrectly as 'Yinnietharra pegmatite'. Further various sources including above have given varying descriptions of its location. After an extensive study, the reference 'Pegmatites of Western Australia' concluded it was 6.7 kilometres south of Pyramid Hill. This included a discussion with Peter Bridge (2003) who was co-author of the existing reference below on clinobisvanite, and listed it as 5 kilometres south of the hill. 'Pegmatites of Western Australia' claim there is no pegmatite 5 kilometres south of Pyramid Hill. This source also provides a map stating its on Bidgemia Station (which is next door to Yinnietharra Station).

Exploratory work and mapping was carried out at the site by AGIP Nucleare in 1974. The pegmatite was pegged by the three Kempton brothers, (Bob, Eric and Les) in 1979. They did limited mining of beryl and tantalum-niobium minerals. It was briefly (and unsuccessfully) explored for scheelite in 1982 before the site was abandoned.

The pegmatite is 300 x 40 metres in size. It has a wall zone of coarse grained microcline-plagioclase-quartz-muscovite and a core of microcline. Trautman (1992) describes the pegmatite as irregular shaped albite variety cleavelandlite masses within the microcline and containing columbite-tantalite and garnet. Mark Calderwood described the pegmatite as massive spessartine, red plagioclase, muscovite and quartz.

It is the type locality for clinobisvanite. The species was discovered by P. Bridge in 1972 after studying material from a collecting trip by the CSIRO to the area in 1971. Later in 1972, R.M. Clarke also discovered the species while studying material collected by Bridge from the Londonderry pegmatite near Coolgardie. A search through the CSIRO uncovered three further locations: Wodgina, Menzies(?), and the Champion Gold Mine near Westonia. In 1973, E.W. Bing found the species on a sample recently submitted from a location 1.3 kilometres north of Corinthia, north of Southern Cross. All locations are in Western Australia. Subsequently it was found that the species had been described beforehand from the Mutala pegmatite area, Mozambique, but had not been named, so the type locality went to the Kempton mine (it was subsequently known by this name several years later).

At the location, clinobisvanite occurs as soft friable yellow coatings, orange globular aggregates, and rarely as small groups of reticulated plates up to 0.1mm across, intergrown with bismutite on spessartine garnet crystals.

Coordinates as per WA Mines Department (GeoView).


Also known as the Tobin Well pegmatite, Marloo 2 pegmatite, and the Arthur River South pegmatite.

The literature has given a number of different locations for this remote site on the eastern fringes of Bidgemia Station, west of the main Yinnietharra mineral field. The reference concludes after studying all available sources, it is 6.7 kilometres due south of Pyramid Hill.

It is the type locality for clinobisvanite. The species was discovered by P. Bridge from the CSIRO in 1972, after studying specimens the organisation collected from pegmatites in the Yinnietharra area in 1971. Later in 1972, R.M. Clarke discovered the species from the Londonderry pegmatite from material also collected by P. Bridge.

A reassessment of the CSIRO collection uncovered a further three localities for the species; Wodgina, Menzies (?), and the Champion Gold Mine near Westonia. In 1973, E.W. Bing from the CSIRO found the species in a recently submitted sample 1.3 kms north-west of Corinthia, north of Southern Cross. All localities were in Western Australia. Subsequently a prior description was found for the Mutala pegmatite area, Mozambique, however the mineral was never named, so the type locality went to this Yinnietharra pegmatite.

Clinobisvanite occurs at the Kempton mine as soft friable yellow coatings, orange globular aggregates, and rarely small groups of reticulated plates up to 0.1mm across, intergrown with bismutite on spessartine garnet crystals. Its is frequently associated with its polymorph pucherite.

The mine is named after the three Kempton brothers; Bob, Eric and Les; who around 1979 pegged the location, and mined beryl and tantalum-niobium to a limited degree. In 1982 it was explored for scheelite by the brothers in conjunction with with a company called UGA, but the deposit was sub-economic.

The pegmatite is 300 x 40 metres in size. It contains a wall zone of coarse grained microcline-plagioclase-quartz-muscovite, and a core of microcline. Massive spessartine, red plagioclase, muscovite, quartz, irregular shaped cleavelandite, columbite-tantalite is common at the site when inspected by one of the authors of the reference many years ago. Euxenite is claimed from the location as black, metamict, vitreous masses, with yellow ochrous blebs of possibly pyrochlore, but both species are yet to be confirmed from the location.

Other Regions, Features and Areas containing this locality

References