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Mt Bischoff mine, Waratah, Waratah district, Tasmania, Australia
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Photo: A. Tuma
Latitude: 41°25'50"S
Longitude: 145°31'20"E
 
 
The Mt Bischoff mine was discovered by farmer and part-time prospector James “Philosopher” Smith in 1871, and for many years was one of the world’s richest tin mines (Groves et al., 1972). After 70 years of continuous production, the Mt Bischoff mine finally closed in 1947. Following mining ventures have mostly been small and spasmodic. Open-cut mining restarted in 2008, with a large open pit swallowing most of the old workings, except the Slaughteryard Face. Mining reserve estimates as at June 30, 2008 are 845,000t at 1.20% Sn. The ore was trucked some 50km to the mill at the Renison Bell tin mine. Mining finished in 2011 and the pit is now flooded, but exploration continues around the pit and deeper reserves are of great exploration interest.

Mt Bischoff was the first major mineral resource developed in Tasmania, with a total production of around 62,000t of metallic tin. The discovery provided the impetus for exploration of other areas of the west coast and the subsequent discovery of other mining areas such as Mt Lyell and Renison.

Geology
Precambrian quartzite, shale and dolomite at Mt Bischoff have been intruded by a radial group of Devonian quartz-feldspar porphyry dykes and breccia dykes, related to the nearby Meredith granite. Tin-base metal sulphide mineralisation accompanies these dykes, and occurs as a replacement of dolomite, as greisenised dykes, and as veins and fracture linings (Groves et al., 1972; Wright & Kwak, 1989, Halley & Walshe, 1995; Sorrell, 1997). Tin mineralisation occurs within a radius of about 1km from the summit of Mt Bischoff, and several silver-lead-antimony deposits surround the mine. Supergene zones were minor.

Dolomite-Replacement Mineralisation
Dolomite-replacement mineralogy is dominated by sulphides (mostly pyrrhotite), Fe-Mg-Mn carbonates, fluorides (fluorite, sellaite), tourmalines and magnesium silicates (chondrodite, norbergite, clinohumite, phlogopite, talc and serpentine), in part as magnesian skarns and “wrigglite” (banded skarn), largely retrogressed. The highest tin grades were found within a quartz-pyrrhotite-topaz-fluorite assemblage (the most strongly altered dolomite replacement rocks) adjacent to the dykes, (now largely worked out). Dolomite-replacement mineralisation is found at the Greisen Face, where talc-pyrrhotite alteration occurs, and at the Slaughteryard Face, where quartz-pyrrhotite alteration and fluorite “nodules” occur.

Dyke Mineralisation
Greisenised dyke rocks are characterised by a white, fine-grained groundmass of quartz and topaz, with orthoclase phenocrysts variably pseudomorphed by siderite, pyrrhotite, quartz, topaz, pyrite, fluorite and cassiterite. One of the most prominent features of Mt Bischoff is the Western Dyke, a greisenised porphyry with cassiterite both disseminated and coating joint surfaces.

Veins and Fracture Linings
Fissure lodes are a late phase of mineralisation, cross-cutting dykes and country rocks. They contain variable proportions of quartz, siderite, tourmaline, topaz, fluorite, cassiterite, wolframite and sulphides (pyrite, pyrrhotite, galena, sphalerite, chalcopyrite, bismuthinite, As-Sb-Bi sulphosalts and stannite).

More than 100 mineral species have been recorded from Mt Bischoff, particularly because of the extensive alteration and large amounts of magnesium and fluorine in the system, producing both attractive and uncommon minerals such as sellaite, franckeite, chondrodite, norbergite, wagnerite and fluoborite.

Mineral List

Mineral list contains entries from the region specified including sub-localities
Actinolite
Albite
'Allanite'
Andradite
Ankerite
Aragonite
Arsenic
Arsenopyrite
Augite
Azurite
Baryte
Bavenite
Berthierite ?
Bertrandite
Beryl
Beudantite
'Biotite'
Bismuth
Bismuthinite
Boulangerite
Bournonite
Brucite
Calcite
Cassiterite
Chalcanthite
Chalcocite
Chalcopyrite
Chondrodite
Chromite
Chrysotile
Clinochlore
Clinohumite
Copiapite
Copper
Corundum
Cuprite
Diaspore
Dickite
Dolomite
Dravite
Elbaite ?
Enstatite
Epidote
Ferberite
Ferro-aluminoceladonite
Fluoborite
Fluorapatite
Fluorite
Foitite
Forsterite
Franckeite
Gahnite
Galena
Goethite
Gold
Goslarite
Graphite
Gypsum
Halite
Halotrichite
Hambergite
Hematite
Hemimorphite
Hisingerite
'Hornblende'
'Hydrogrossular'
Isokite
Jamesonite
Kaolinite
Lepidolite
Luinaite-(OH)
Magnesite
Magnetite
Malachite
Marcasite
Melanterite
Microcline
Molybdenite
'Monazite'
Morinite
Muscovite
var: Illite
Natrolite
Norbergite
Olenite
Opal
Orthoclase
Owyheeite ?
Palygorskite
Phenakite
Phlogopite
Prosopite
Proustite
Pyrargyrite
Pyrite
Pyrolusite
Pyrophyllite
Pyrostilpnite
Pyrrhotite
Quartz
var: Smoky Quartz
Ralstonite
Rutile
Schorl
Scorodite
Sellaite
Siderite
Sillimanite
Smithsonite
Sphalerite
Stannite
Stibnite
Sulphur
Sylvite
Talc
Teallite
Tetrahedrite
Thorianite
Titanite
Topaz
'Tourmaline'
Tremolite
Tungstite
Vivianite
Vonsenite
Wagnerite
Wavellite
Weberite
'Wolframite'
Wollastonite
Xenotime-(Y)
Zircon


151 entries listed. 123 valid minerals.

Localities in this Region

Australia

The above list contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.

References

- McAndrew, JA, 1965, Geology of Australian ore deposits. AIMM.
- Anon, 1970. Catalogue of the Minerals in Tasmania. Geol. Surv. Record No. 9, Tasmania Department of Mines.
- Groves, D.I., Martin, E.L., Murchie, H., & Wellington, H.K., 1972. A Century of Tin Mining at Mount Bischoff, 1871-1971. Geological Survey Bulletin No. 54. Tasmanian Department of Mines.
- Wright, J.H. and Kwak, T.A.P., 1988. Endogreisen, brecciation and fluid activity at the Mount Bischoff Sn-deposit, North-west Tasmania, Australia. Journal of Metamorphic Geology 6, 629-650.
- Econ Geol (1989) 84:551-574
- Burrett, C.F. & Martin, E.L., eds., 1989. Geology and Mineral Resources of Tasmania., p. 383-398. Geological Society of Australia Inc., Special Publication 15.
- Rocks & Min.: 22:326.
- Dickens, G., 1995. Mining in Tasmania – a brief History. Tasmanian Geological Survey Record 1995/11.
- Halley, S. & Walshe, J.L., 1995, A re-examination of the Mt Bischoff cassiterite sulphide skarn, Western Tasmania. Economic Geology, 90, 1076-1683.
- Sorrell, S, 1997. Mt Bischoff – Mountain of Tin. Mineralogical Society of Tasmania, Newsletter, 20, 7-16.
- Bottrill, R.S. and Baker, W.E., 2008. Catalogue of Minerals of Tasmania. Mineral Resources Tasmania.



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Copyright © Jolyon Ralph and Ida Chau 1993-2014. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of thousands of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
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