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Princess Mine
Princess
Mine, Moina, Tasmania at crocoite.com
Photos and specimens - Steve Sorrell - crocoite.com
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Princess Mine
Arsenolite,
Arsenopyrite
Bismuthinite
Fluorite
Monazite
Muscovite
Quartz
Siderite
Topaz
Urquhart's
Claim - The Princess Mine
The Princess mine, Moina, originally known as Urquhart's Claim after the
original lease holder, is located on the northeast slope of Dolcoath Hill,
overlooking the Cethana dam, part of the hydroelectric scheme on the Forth
River. It is one of a number of mines in the region that have been worked
for tin, tungsten and/or bismuth. The largest of these is the Shepherd
and Murphy mine. Other mines include the All Nations, Dolcoath, Sayers
(well known for its beryl), and Pig and Whistle.
The deposit was discovered by Warwick Castle in 1908, but mining activity
ceased around 1918. Seven exploratory trenches were originally cut, but
little of value was found. Warwick Castle himself controlled the mine
for a while and extracted wolframite and bismuthinite, the only two minerals
noted in the Catalogue of the Minerals of Tasmania.
This
mine worked two well defined veins up to 200 mm wide, containing bismuthinite
and wolframite in a quartz matrix, with topaz and fluorite, in pegamtites
near the top of a biotite granite host (Reid, 1919). Bismutite, tungstite
and ferritungstite were also recorded in the oxidised zones. Bismuthinite
reportedly occurred in long bladed crystals and delicate acicular forms.
Numerous small wolframite-quartz veins occur in the quartzite overlying
the granite. High quality smoky quartz crystals to 150 mm long, some enclosing
bismuthinite and wolframite, occur in the lodes. The deposit has been
developed in a shaft, open cut, adit and trenches, and proved the lode
continuous over 100 m vertically.
Recent years have seen the mine being worked for mineral specimens, mainly
topaz and quartz, and is currently under lease and being worked by John
Wilson and Richard Wolfe.
There
are three levels of workings still visible, with most activity centered
around the top and bottom levels. The top level consists of a small adit
that has to be pumped out before entering, where pockets of clay can,
and have provided some stunning blue topaz crystals.
The range of minerals found in the top level include quartz, wolframite,
fluorite, bismuthinite, beryl and muscovite. The bottom level adit is
proving to be interesting with a range of minerals having been identified,
including bismuthinite, fluorite and monazite.
Arsenolite
- Powdery white masses on arsenopyrite are probably arsenolite.
Arsenopyrite - Found as masses and as individual crystals to a few millimetres
across within patches of massive arsenopyrite.
Beryl - Small beryl crystals have been reported from this mine.
Bismuthinite - Occurs as bright silvery crystal aggregates to 4 cm long
and as micro needles in small cavities in fluorite, also as inclusions
within quartz or fluorite.
Bismutite - Reported in the oxidised zone.
Chlorite - Greenish material occurring as inclusions in topaz. The exact
species is unknown.
Ferritungstite - Reported in the oxidised zone.
Fluorite - As mostly green massive material, with occasional cubic or octahedral
crystals. This material is said to fluoresce brightly, although does not
under long-wave UV. It does however, possess thermoluminescence, glowing
a creamish colour for some time after being exposed to a bright light
source. This phenomena is apparently how the fluorite was first located,
caused by the miner's cap lamps! Fluorite also occurs as tiny colourless
or pale to dark purple cubes and rounded or odd-shaped individual crystals
on arsenopyrite crystals.
Monazite-(Ce)
- A single specimen of resinous orange-brown colour has been found and
is probably monazite-Ce.
Muscovite - This occurs mostly as masses of flaky crystalline aggregates,
but well-formed mica "books" can also be found.
Quartz - This mineral occurs in three main forms, as massive veins, as
crystals, mainly smoky, to many centimetres in length, and as sugary crystals
coating other minerals including bismuthinite, quartz and muscovite.
Siderite - An orange carbonate mineral has been tentatively identified
as siderite.
Topaz - Apart from the blue topaz mentioned above, colourless crystals
also occur, but only rarely on matrix.
Tungstite - Reported in the oxidised zone.
Wolframite - Usually as black masses, rarely as crystals.
Access to the mine is strictly only with permission from the lease holders, to whom thanks are offered for the opportunity to visit and collect specimens.
references : http://www.crocoite.com/locations/princessmoina.htm
