MINERAL SPECIES FROM BROKEN HILL, NEW SOUTH WALES AND ITS OUTLYING REGIONS
Last Updated: 15th Jan 2022By Peter Andersen
MINERAL SPECIES FROM BROKEN HILL, NEW SOUTH WALES AND ITS OUTLYING REGIONS
By Peter Andersen
P.O. Box 2418
Mildura
Victoria 3502
Australia
Email: pjandersen50@hotmail.com
It is pretty well understood that everyone who collects minerals knows that the main Broken Hill lode is one of the great mineralogical rainforests of the world with almost 300 different mineral species being recognized as occurring there. What very few mineral collectors also realize is that there is also a wealth of minerals found in various deposits within a 100 kilometre radius around the main township of Broken Hill (see Figure 1). These deposits could be small isolated occurrences such as the deposit of the rare barium feldspars found at the local piggery to large commercially viable deposits that were once mined many years ago and in some cases are still being mined even today. Even the highly metamorphosed Precambrian rocks that make up the hills around Broken Hill are full of many examples of well crystallised and often quite showy minerals. One example that comes to mind is the very large individual crystals of almandine, up to 30 cm in size, that occur in some of the local chlorite schists as a result of retrograde metamorphism that occurred in the Willyama Complex around 500 million years ago.
The mineral occurrences that occur within the Broken Hill region can basically be summed up as being:
1/ The main Broken Hill lode orebody that has now been continually mined for over a century.
2/ Smaller outlying orebodies that once were of economic importance. Some such as the orebody known as the Pinnacles Mine were even re-established as an operation and commercially worked this century. There are three recognized types of these smaller outlying orebodies and they are:
Broken Hill type deposits which occur in a characteristic sequence of high grade metamorphic rocks. These rock units include gneisses, amphibolite and small banded iron formations. The ore mineralisation of Broken Hill type deposits occur in narrow units of the ore horizon which are parallel to the layering of the enclosing sillimanite rich and quartz rich gneisses. The primary ore mineralisation of these lodes was formed at the same time as the enclosing original sedimentary and volcanic rocks and therefore underwent the same high temperatures and pressures of metamorphism that this region has been subjected to over the geological time from original deposition to present day. Broken Hill type deposits are characterised by the minerals galena, sphalerite, chalcopyrite, pyrrhotite, quartz (which is coloured blue due to the stress that the quartz was subjected to during metamorphism), spessartine, rhodonite, gahnite and a high lead bearing orthoclase that is coloured green. Examples of Broken Hill type deposits include the Pinnacles Mine, the Postosi Open Pit, the Parnell Mine, the Southern Cross Mine, the Melbourne Rockwell Mine and the Nine Mile Mine.
Thackaringa type deposits which occur in a characteristic sequence of lower grade metamorphic rocks when compared to the metamorphic rocks that the Broken Hill type deposits occur in. A major characteristic of Thackaringa type deposits is that the ore minerals occurred in narrow quartz-siderite veins which cross cut the layering of the enclosing rocks. These deposits are very common in shear and fault zones and their mineralogy is rather simple when compared to that of the Broken Hill type deposits. Most of the Thackaringa type deposits were restricted to the western and northern parts of the Willyama Complex and they were formed later than the enclosing metamorphic rocks. The veins that make up the Thackaringa type deposits occur in retrograde shear zones cutting across the retrograde schistosity (Barnes, 1980). Because the Thackaringa type deposits were formed later than the metamorphic rocks that enclose these orebodies it is generally believed that they originated as a result of the preferential sweating out of base metals, such as lead and silver, from the surrounding Broken Hill type deposits during the closing stages of the high grade metamorphic epogenic processes (Plimmer, 1977). The ore mineralogy of the Thackaringa type deposits includes galena, chalcopyrite, pyrite and tetrahedrite. In these deposits sphalerite is notably absent or else it is a very minor constituent and the galena is quite argentiferous. There are no minerals that are quite characteristic of the Broken Hill type deposits, such as the blue quartz, spessartine, rhodonite, gahnite and green orthoclase, present in the Thackaringa type deposits. Due to the extensive weathering of these orebodies, there occurred extensive enriching of silver above the watertable and it was these silver values that made these deposits economically viable as a mining operation. Mining of the Thackaringa type deposits finished once the enriched silver values present in the ore above the watertable had been extracted. Because of this the Thackaringa type deposits had a very short mining history and a shallow depth of operation. Examples of Thackaringa type deposits include the mines that worked the orebodies around the settlements of Thackaringa and Silverton.
Other heavy and base metal mineralization deposits which include the gold deposits of the Mulculca area near Red Hill in which the gold is in quartz associated with pyrite; the platinum deposits to the east of Broken Hill; the copper deposits of Silverton, where the Umberumberka East Copper Mine produced at least 100 tons of high grade copper ore, and to the south east of Broken Hill where the Copper Blow yielded up some tens of tons of copper ore.
3/ Pegmatite occurrences, some of which were economically viable and are still being worked this century. The economic minerals of these pegmatites included beryl, cassiterite, muscovite and orthoclase. Examples of pegmatite in the Broken Hill region that were worked commercially include the Triple Chance Mine, Egebek Quarry, Gava’s pegmatite, Wilson’s Pegmatite, the Huel Bijerkerno Mine, the Lady Don Mine, the Poolamacca Tin Mine, the Trident Mine and the Yanco Glen deposit which produced a few tonnes of Wolframite ore.
4/ Minerals present in the metamorphic rocks, some of which were once economically viable and have been worked on a commercial basis every now and then. The economic minerals include almandine, sillimanite, kyanite etc. Examples of these commercially worked deposits in the metamorphic rocks include Ireland’s Quarry, O’Connell’s Kyanite Quarry and Mawby and Fishers Quarry
Some of the more notable mines, pegmatites, other deposits and individual localities that are located in the Broken Hill region and which excludes the main Broken Hill orebody (see Figure 1) include:
1/ The Pinnacles Mine
The orebody that occurred in the severe buckle west of the South Pinnacle Hill was named the Pinnacles Mine and it is located 14 kilometres to the south west of the main Broken Hill lode. This orebody has a very similar primary mineralogy to that of the main Broken Hill lode and so has been designated as being a Broken Hill type deposit. The outcrop of this lode was discovered in late1884 by two prospectors, Maiden and Pretty, and to date about 300 000 tonnes of ore has been extracted from this lode and processed for its metal values. The orebody of the Pinnacles Mine is very siliceous and the rather narrow orebodies have been tightly folded. The mineralogy of this mine was very similar to that of the main Broken Hill lode but was not as extensive in the number of different mineral species present in that fabulous deposit. The main primary minerals present in the Pinnacles Mine were galena, gahnite, hedenbergite, loellingite, green orthoclase, pyrrhotite, quartz, spessartine, sphalerite and tephroite. There was also a limited oxidised zone that produced small amounts of azurite, cerussite, malachite, and pyromorphite. The mine has change hands a number of times and even in the early part of the 21st century this particular mine was being operated as a source of ore by the Consolidated Broken Hill Company. The ore dumps of the Pinnacles Mine became a real bonanza for mineral collectors when 60 000 tonnes of oxidised ore from the Kintore and Block 14 open Cuts was extracted and dumped there for processing at the end of last century by the Consolidated Broken Hill Company that now owned and operated his mine. It was really great that mineral collectors were given access to this ore by the Pinnacles mine operators as it was a superb and accessible source of the fabulous well crystallized and rare minerals that the Broken Hill oxidised zone was famous for producing. In fact a number of species new to Broken Hill were found in the dumped oxidised ore from the Kintore and Block 14 open Cuts, identified and described in time to be added to the mineral descriptions of the 1999 book on the mineralogy of Broken Hill.
2/ Other Broken Hill Type Deposits
There are a number of other orebodies in the Broken Hill district that have mined Broken Hill type deposits as their source of ore. These orebodies include the Potosi Open Pit which is a small deposit located 2 km to the east of Broken Hill and now has the distinction of being a type locality for two mineral species: hoganite and paceite; the Southern Cross Mine and the Parnell Mine which are very close to one another and the Nine Mile Mine that is situated 9 km to the north west of the main Broken Hill lode. The Nine Mile mine has the distinction of being a mine in the Broken Hill district that had no ore raised from its operation, even though a shaft was sunk to a depth of 60 metres and two levels were driven at 25 and 50 metres. This mine was opened in 1887 by a syndicate called the Nine Mile Silver Mining Company and obviously they went broke! Very nice crystals of the zinc spinel member, gahnite, can still be found at this locality. The Melbourne Rockwell Mine, which is located 13 km to the south east of the main Broken Hill township at Little Broken Hill is the type locality for the mineral ecandrewsite and it is also has the distinction of being the only other locality in Broken Hill to have rhodonite present as part of its mineralogy.
3/ The Mines and Economic deposits of Silverton
Silverton is a very small settlement 22 km to the west of the main Broken Hill township. Silverton’s claim to fame is that the mines around this town were being worked for their ore values several years before the discovery of the main Broken Hill lode by the Prussian army deserter that had changed his name from Jerome Freiherr von Pereira to Charles Rasp. Silverton is still an active settlement as it now exists on tourism and it even has the distinction of having being the site for the filming of several feature films. The mines that worked the small lodes around Silverton were all extracting ore from Thackaringa type deposits and there were a number of these. Silver was the main metal being extracted from these mines and a number of silver bearing minerals are to be found occasionally in old collections today. Some of the mines in the Silverton area that were worked for their silver content back in the late 19th century included:
The Umberumberka Mine. This mine worked an orebody that was 5 km to the west of Silverton itself. It was discovered in 1882 and during its short life produced around 20 000 tonnes of high grade silver ore. It was the discovery and establishment of this mine that gave rise to the township of Silverton. The mine reached a depth of 130 metres and there were 7 levels in it to access the rich silver ores. These rich silver ores were made up of silver bearing galena along with silver bearing minerals such as argentite, chlorargyrite, silver and stephanite. Other notable minerals found in this deposit included cerussite, nadorite and the largest crystals of phosgenite (to 5 cm in length-Pring, 1987) found in any of the mines of the Broken Hill district. The silver bearing ores of the Umberumberka Mine occurred in sheared re-metamorphosed rocks which are associated with large bodies of amphibolites and pegmatites.
The Daydream Mine. This mine worked an orebody that was 16 km to the north east of Silverton itself. Its orebody was discovered in 1882 by a prospector named Joe Meech and during its short life produced around 30 000 tonnes of high grade silver ore assaying around 60-600 ounces of silver per ton. The total silver production from this mine was in the vicinity of 96 000 ounces. (Andrews, 1922). The lodes of the Daydream Mine occurred within narrow shear zones at the footwall of granite dykes and the outcrop of this lode was 30m long and varied from 0.5m to 2.5m in width (Leach, 1997).The mine reached a depth of 150 metres and there were a number of shafts sunk and levels driven to access the rich silver ores of this lode. These rich silver ores were made up of silver bearing galena along with silver bearing minerals such as argentite, boleite, chlorargyrite, silver, stephanite and tetrahedrite. Other notable minerals found in this deposit included cerussite, fluorite, malachite, phosgenite and siderite. Like all the other mines that worked the Thackaringa type deposits in the Broken Hill district the Daydream mine had a short history of operation and the company ceased mining operations once the rich silver bearing weathered ore above the water table was extracted and processed. These days the Daydream mine is operated as a tourist attraction and this mine gives its visitors a chance to see how mines operated at the turn of the last century and even go underground through its narrow tunnels.
Other mines in the Silverton district that mined Thackaringa type deposits included the Apollyon Mine, the Hen and Chicken Mine and the Silver King Mine.
A pegmatite 1.5 km from Silverton was named Gava’s Albite pegmatite and operated for some time as a source of albite for high quality ceramics. This pegmatite has intruded and slightly sheared an amphibolite rock and is composed mainly of albite with minor associated muscovite, quartz and beryl. Gava’s Albite pegmatite has the distinction of being the only pegmatite in the Broken Hill district that has actually produced gem quality beryl crystals, but they are no larger than 1 cm in size (Plimmer, 1977).
4/ The Mines, Pegmatites and Metamorphic Minerals of Thackaringa
The Mines of Thackaringa. Thackaringa has the distinction of being the locality where the discovery of the first orebodies in this far western district of New South Wales occurred. It was back in 1876 that Paddy Green (who was living in Menindee at that time) discovered the first lode to be pegged in this region of outback Australia. Numerous prospectors followed and soon a number of mines were being operated in this remote region of New South Wales that had been named Thackaringa and was located 35km to the south west of what would soon become the main regional town of Broken Hill. A small township grew up around the discovery of these small silver rich orebodies and there was even a school along with the numerous “hotels” (which were really just basic watering holes for the many miners) that always seems to sprout around a group of mines when they come into existence. Nowadays there is no sign whatsoever that here once existed at Thackaringa a thriving small community except for the large number of shafts that are still there. The main mine at Thackaringa was the Pioneer Mine which operated from around 1884 through to 1925 and reached a total depth of 150 metres. Other mines in this district included the Gipsy Girl but the depth of its main shaft was only 70 metres and it had ceased ore production by 1892; the Lily Mine, the Homeward Bound Mine, the Thackaringa Mine, The Gipsy boy Mine, Gipsy Queen Mine, Lady Brassey Mine and the Hercules Mine. In all 27 named mines are recorded but production records are fragmental. The total ore produced from all of the Thackaringa mines was only around 30 000 tonnes and most of this ore production appears to have come from two mines: The Pioneer Mine records show that it produced 20 000 tonnes of ore and the Gipsy Girl Mine records show that it produced 10 000 tonnes of ore. All of the operating mines at Thackaringa were extracting silver bearing ore from Thackaringa type deposits, which at Thackaringa were vein type deposits located within the Thackaringa-Pinnacles Shear Zone. In the Thackaringa deposits the primary ore minerals, mainly made up of argentiferous galena, arsenopyrite, chalcopyrite, covellite, cubanite, gersdorfite, lollingite, marcasite, pyrite pyrrhotite, sphalerite, tetrahedrite and valleriite, were located within narrow steeply-dipping quartz siderite veins. Siderite also made up the core of the vein as well. The margin of these siderite veins was composed mainly of quartz, chalcopyrite, pyrite and minor sphalerite. Oxidation of the primary ore minerals resulted in the formation of extensive deposits of supergene minerals, such as chlorargyrite, which was the main source of the silver that was being produced from these mines.
The veins of the Thackaringa lead silver mines varied in width from a few inches (about 5 cm) up to 3 or more feet (1 or more metres) and typical descriptions of good ore produced by a number of these mines (taken directly from King, 1953b) are:
Lily Mine-vein 6 to 12 in. wide, cerargyrite with earthy malachite, 18 tons bagged, assaying 520 oz. Ag per ton and 26% Pb.
Gipsy Girl-4 to 14 in. of galena with 2ft. of iron ore (siderite or limonite) and quartz beneath. The ore yields 50 oz. Ag per ton and 72% Pb.
Pioneer-assays ranged from 56% Pb, 40 oz. Ag per ton, to 25% Pb, 12 oz. Ag per ton. Ore 6 ft wide in places.
Homeward Bound-ore 30 to 42 in. wide, one “small” parcel 40oz. Ag per ton, 1 oz. Au per ton, 60% Pb.
Hercules-200 tons shipped, assaying 40 oz. to 80 oz. Ag per ton, 50% to 70% Pb.
The Pegmatites of Thackaringa. As well as the numerous mines that worked the Thackaringa type deposits there were also a number of pegmatites that were of commercial viability. The best known pegmatite at Thackaringa is the Triple Chance Mine that was operated for many years by a real hardy soul by the name of Mrs Tess Alfonzi. This locality produced 37 000 tonnes of feldspar, 3000 tonnes of quartz, 350 tonnes of beryl and 184 tonnes of muscovite. The late Mrs Tess Alfonzi was very proud of the fact that beryllium extracted from Triple Chance Mine beryl was used in the Apollo 11 Luner Lander and so had been to the moon. The mineral lease of the Triple Chance Mine has once again been taken up and commercial mining of its economic minerals has once more been undertaken at this deposit. Other pegmatites that have been commercially operated in the Thackaringa region included the Egebek Quarry; Lady Beryl; Wilson’s Pegamatite (which was operated by Johnny Wilson as a source of feldspar and this pegmatite contained quite rare primary phosphate minerals that included barbosalite, cyrilovite, triplite and wolfeite (Plimer, 1979). Other collector quality minerals that were present in this pegmatite include beryl, bertrandite, muscovite, quartz, and possibly the best crystals of microcline from an Australian locality that were collected by the author in 1983); Baker’s Pegmatite (this was a source of the rare mineral davidite) and an unnamed deposit near the intercontinental railway line that mined very large crystals of annite formed in a pegmatite near the edge of the Thackaringa-Pinnacles Shear Zone.
The Metamorphics of Thackaringa. There have been a number of commercial mining operations established to extract minerals from the metamorphic rocks around Thackaringa. These include O’Connell’s Kyanite Quarry that was established 12 km to the south west of Broken Hill to mine refractory grade kyanite; Mawby and Fisher’s Quarry that was established to mine a pod of sillimanite and this quarry also produced nice crystals of diaspore, corundum and clinozoisite as well; Ireland’s quarry that was established to mine almandine crystals in a chlorite schist for the abrasive industry. Ireland’s Quarry is located 25 km to the south west of Broken Hill within a large shear zone called the Thackaringa-Pinnacles Shear Zone in which the high grade metamorphic gneissic rocks have been re-metamorphosed into lower grade almandine-chlorite schists. Such re-metamorphism of higher grade metamorphic rocks into metamorphic rocks of a lower grade is called retrograde metamorphism and the individual almandine crystals formed in these schists grow to incredible sizes and the almandine crystals from Ireland’s Quarry certainly confirm this as they can be up to 30 cm in size. This retrograde metamorphism occurred around 500 million years ago and the Thackaringa-Pinnacles Shear Zone is the principal zone of re-metamorphism in the Broken Hill district. Other localities in the Thackaringa region that have produced mineral specimens include the Repeater Station, Belle View, Big Hill, Peak Hill and the Twenty Mile Sillimanite Pit. The minerals found in the metamorphic rocks at these localities include almandine, annite, corundum, epidote, ilmenite, kyanite, magnetite, magnesite, rutile, schorl, sillimanite, staurolite, titanite, etc.
5/ The Euriowie Pegmatites
Euriowie is now an abandoned settlement that was once established 80 km north east of Broken Hill. In 1884 commercial amounts of tin were discovered in a number of pegmatites in a remote region of western New South Wales which was to be then named Eurowie. This discovery of commercial amounts of tin led to the establishment of the Euriowie township, which was a small settlement that once had 700 people, two banks, three stores, four hotels, several whorehouses and a racecourse. The greatest mining activity was around the turn of last century and by 1910 most of the rich tin ore had been extracted from all of the pegmatites in the area and this resulted in the township of Euriowie being abandoned. The largest mine at Euriowie was the Huel Byjerkerno Mine and other mines of this region included the Lady Don Mine, the Poolamacca Tin Mine, the Trident Mine, and quite a few others as there were over 800 leases pegged in this district at one time. The minerals that were present in these tin bearing pegmatites included albite, amblygonite, augelite, beryl (caesium rich), cassiterite, columbite, corundum, elbaite, fluorapatite, fluorite, lazurite, lepidolite, morenite, muscovite, paragonite, petalite, quartz, rutile, schorl, svanbergite, tantalite, topaz, etc. There have also been small amounts of azurite, cuprite, malachite and pyrrhotite found in the pegmatites of this area as well.
6/ The Platinum Group Mineral Deposits
(iv) 20 km to the east of Broken Hill there are a number of small ore deposits that have been extensively oxidised and contained in the gossans of these deposits is a number of very rare platinum group minerals that are only present as minsicule grains. These gossan deposits containing these platinum group minerals are present at Mulga Springs, Little Darling Creek, Round Hill (Moorkaie Hill) and Red Hill. The platinum group minerals that have been identified to date include platinum alloys such as braggite, sperrylite and native platinum; and palladium alloys such as froodite, mertiete II, paolovite and a number of unnamed phases of palladium-copper-bismuth-mercury and telleurium alloys. There are also secondary base metal minerals present in all of these gossans including anglesite, azurite, barite, cerussite, chalcocite, chrysocolla, iodargyrite (the only known occurrence of this mineral in the Broken Hill district outside of the main Broken Hill lode) and malachite. Primary minerals found in these gossans include arsenopyrite, bismuth, gold, galena, ilmenite, pentlandite and pyrite.
7/ Other Localities
A number of other localities exist in the Broken Hill district that have produced unusual minerals or well crystallised specimens. These include:
(i) Thorndale Station which is located 30 km to the east of Broken Hill and it is here that gem quality crystals of lime green titanite have been collected from a coarse grained clinopyroxene-amphibole-plagioclase mafic granulite. This mafic granulite has been partially replaced by a retrograde assemblage consisting of calcite, amphibole and titanite (Plimmer 1983). These gem quality titanite crystals are up to 0.5cm across and are present in transgressive white calcite veinlets that are around 1 cm in width.
(ii) McDougalls Well, located 80 km to the north of Broken Hill and is accessed via Corona Station, is the premier locality in New South Wales for amethyst. The amethyst, smoky and other types of quartz occurs here as veins in schists and slates of the Torrowangee Group of metamorphic rocks. The quartz crystals at this deposit were formed during the metamorphism that happened to these rocks 500 million years ago and they can be found here in a range of colours that includes purple (amethyst), black (smoky), green (this colour being caused by the long period of exposure to sunlight of the purple crystals - Plimer, 1977) and colourless. These quartz specimens are very attractive and can still be collected today.
The Piggery, which is located near the abattoirs in Ryan Street, and the Waterworks Hill outcrops of rare barium feldspar minerals was originally described by Sir Douglas Mawson and both of these localities are within the suburban confines of the Broken Hill township. These feldspars occur as small light-coloured masses within a coarse grained granite gneiss and the barium feldspar group mineral species identified from here include armenite, celsian and hyalophane.
In the southwest corner of the Broken Hill Racecourse there was a small pegmatite outcrop that had a shaft sunk on it for the purpose of extracting commercial amounts of whatever minerals could be found. The mineral collection of the Museum Victoria has three specimens in its collections from this pegmatite and they are manganocolumbite and goethite and these two speciemns were originally in the mineral collection of Sir Maurice Mawby and they came into the museum’s mineral collection when that Augustus person donated his personal mineral collection to the museum back in 1977 just before he croaked.
The mineral collection of the Museum Victoria has possibly the world’s biggest collection of minerals from the Broken Hill district of New South Wales with a holding of over 3500 specimens. Some of the more obscure localities that they have represented by having mineral specimens from these localities being registered in this collection include Clondes Property, Great Western Mine, Hinspeter Mine, Huonville Station, Kantappa Tin Mine, Maybell, Mayflower Mine, Mount Gipps, Mount Rutland, Mulga Springs, Parramoota (this locality is a misspelt Purnamoota- see Figure 5), Rockwell Paddock, Sterling Vale (misspelling for Stirling Vale- see Figure 5), Thompsons Tank and Waukeroo Tin Field.
The Minerals from the slags of Broken Hill. In order to process the ore that it was mining from its leases on the Broken Hill lode, the Broken Hill Proprietary Company ended up erecting on its leases 15 smelters before the end of the 19th century. Other mines which also had smelters to process the ore that was extracted from their mining operations included the British Mine, the Block 14 Mine, the Central Mine and the South Mine. By the time that the ore smelting operations had finished for good in Broken Hill, which was in 1898, there were an estimated 800 000 tonnes of slag dumped on a number of the mining leases. Over the next 100+ years these slags would undergo secondary alteration due to normal weathering processes and this resulted in the growth of a number of secondary mineral species within the gas bubbles of the slags. These secondary minerals that had now been formed in these slag gas bubbles were subjected to a scientific study by the very advanced amateur mineralogist, Peter Elliot, and he published his results in the 1997 special Broken Hill issue of the Australian Journal of Mineralogy. Peter Elliot’s study of these minerals resulted in the following species being identified as occurring in the slag deposits of Broken Hill: anglesite, aragonite, bechererite, brochantite, calcite, caledonite, cerussite, connellite, cumengite, cuprite, gypsum, hydrozincite, jarosite, ktenasite, lanarkite, leadhillite, linarite, malachite, namuwite, plumbojarosite, posnjakite, schulenbergite, serpierite, sulphur and several unknowns. The IMA Commission on New Minerals and Mineral names has ruled that chemical compounds formed by the actions of geological processes on anthropogenic (man made) substances, such as slags, will not be considered as being valid mineral species (Nickel, 1995).
Below is an alphabetical listing of as many different mineral species that the Author knows to occur in the Broken Hill district. This list not only includes the well known mineral species from the main Broken Hill orebody but also as many different species that the author has been able to track down from other localities within a 100 km radius of the main Broken Hill township. I am aware that this list is not completely exhaustive in the listing of all species known to occur in the Broken Hill district but it is a start and it is a good basis for anyone that is interested in the range of minerals already recorded from this incredible mining district. The following abbreviations have been used in this table to delineate where the minerals occur in the district of Broken Hill:
1/ MLOZ= main lode-oxidised zone
2/ MLSZ= main lode-supergene zone
2/ MLPO= main lode-primary ore zone
3/ MLCR=main lode-country rocks
4/ CML= the lode of the ABH Consols mine
5/ OLOZ= other lodes-oxidised zone
6/ OLPO= other lodes-primary ore zone
7/ M= occurrences in the Broken Hill metamorphic rocks
8/ P= occurrences in the Broken Hill pegmatites
9/ I= occurrences in altered Intruded ultramafic bodies.
10/ S= post mining minerals found in slags from the smelting processes of the various mines.
Where possible I have also indicated in the very last column some of the names of the main mines, commercial operations and interesting localities that have produced these various minerals. I have also included some comments about some of the post mine minerals in this column as well when they are relevant. Minerals in capital letters only are those that were first described and named from the district of Broken Hill. Those minerals listed in small letters are those that have been described by previous mineralogists but there is an actual need of confirmation of identity by chemical analysis or X-ray diffraction and also many of the secondary slag minerals have been listed this way as well since the IMA Commission on New Minerals and Mineral names does not consider these type of minerals as being a valid species. There are some unknown species that are listed that still needs work done on them to confirm their mineral identity. In these cases there just is not enough of these minerals available at present to be able to go any further with their identification.
ACKNOWLEDGEMENTS
I would like to acknowledge the help that the Dr Bill Birch (the senior curator) and Dermot Henry (collection manager) of the Museum Victoria’s Department of Mineralogy gave in allowing me to access their data base and print off the records that I needed. These records have been invaluable in compiling the data table of the minerals of the Broken Hill district.
BIBLIOGRAPHY
Andrews, E.C. (1922a) The Geology of the Broken Hill District. Memoirs of the Geological Survey of New South Wales 8, Sydney, Australia, 257 p.
Andrews, E.C. (1922b) Notes on the geology of the Broken Hill district. Economic Geology, 17, 470-490.
Barnes, R.G. (1980) Types of mineralization in the Broken Hill Block and their relationship to stratigraphy. In: Stevens, B.P.J. (Editor) A Guide to the stratigraphy and mineralisation of the Broken Hill Block, New South Wales. Records of the Geological Survey of New South Wales, 59-60.
Birch, W.D. (1999) The minerals. In: Birch, W.D. (Editor) Minerals of brokenhill. Broken Hill City Council in conjunction with Museum Victoria, Melbourne, Victoria, Australia, 90-262.
Birch, W.D, (Editor-1999) Minerals of brokenhill. Broken Hill City Council in conjunction with Museum Victoria, Melbourne, Victoria, Australia, 289 p.
Bosworth, J. (2002) What’s new in Australia. Australian Journal of Mineralogy, 8 (2), 80-81.
Day, B. (1998) What’s New in Australia. Australian Journal of Mineralogy, 4 (1), 40-41.
Elliot, P. (1997) Minerals of the Slags from Broken Hill, New South Wales. Australian Journal of Mineralogy, 3 (1), 77-83.
Elliot, P., Brugger, J., Pring, A., Cole, M.L., Willis, A.C., and Kolitsch, U., (2008) Birchite, a new mineral from Broken Hill, New South Wales, Australia: description and structure refinement. American Mineralogist 93, 910-917.
Elvy, S.B., Gray, N.D., McAndrew, J., Williams, P.A., and French, D.R. (1998) Platinum group minerals from the Broken Hill district, New South Wales. Australian Journal of Mineralogy, 4 (1), 33-39.
Johnson, J. E. (1956a) Specimen minerals of the Egebek pegmatites, near Broken Hill. The Australian Amateur Mineralogist, March 1956, 5-7.
Johnson, J. E. (1956b) Further notes on the specimen minerals of the Egebek Ming Field, Broken Hill. The Australian Amateur Mineralogist December 1956, 101-102.
King, H.F. (1953a) The Pinnacles Mine and its environment. In: Edwards, A.B. (Editor) Geology of Australian Ore Deposits. Australasian Institute of Mining and Metallurgy, Melbourne, Victoria, Australia, 677-684.
King, H.F. (1953b) The Thackaringa Mines. In: Edwards, A.B. (Editor) Geology of Australian Ore Deposits. Australasian Institute of Mining and Metallurgy, Melbourne, Victoria, Australia, 685-686.
King, H.F., and Thomson, B.P. (1953) The geology of the Broken Hill district. In: Edwards, A.B.(Editor) Geology of Australian Ore Deposits, Australasian Institute of Mining and Metallurgy, Melbourne, Victoria, Australia, 533-577.
Lawrence, L.J. (1967) Mineralogy and textures of Thackaringa sulphide ores. Proceedings of the Australasian Institute of Mining and Metallurgy, 222, 85-94.
Lawrence, L.J., Ramsden, A.R., and Graham, I.T. (1999) On the Oxidation of Dyscrasite and associated Minerals of the Consols Lode, Broken Hill, New South Wales. Australian Journal of Mineralogy, 5 (2), 63-68.
Leach, J.D. (1997) The Daydream Mine, Silverton, New South Wales. Australian Journal of Mineralogy, 3 (2), 103-109.
Lewis, B.R., Forwood, P.S., and Roberts, J.B. (1965) Geology of the Broken Hill lode reinterpreted. In: McAndrew, J. (Editor) Geology of Australian Ore Deposits, Volume 1, Proceedings of the 8th Commonwealth Mining and Metallurgy Congress. Australasian Institute of Mining and Metallurgy, Melbourne, Victoria, Australia, 319-332.
Lishmund, S. R. (1982) Non-metallic and tin deposits of the Broken Hill district. Geological Survey of New South Wales, Bulletin 28, 176p. Department of Mineral Resources, Sydney, Australia, pub.
Mawby, M. (1975) The Contribution of Broken Hill, N.S.W. Australian Mineralogist, 1 (1), 1.
Nickel, E.H. (1995) Definition of a Mineral. The Mineralogical Record, 26, 437-438.
Plimer, I.R. (1977) Mineral Collecting Localities of the Broken Hill district. Peacock Publications, Hyde Park, South Australia, Australia, 65p.
Plimer, I.R. (1981) Notes for the 1981 Mineralogical Society of Victoria’s excursion to Broken Hill. Unpublished but distributed to all members that participated on this excursion.
Plimer, I.R. (1982) Corundum-bearing schist from the Willyama Complex, Thackaringa, N.S.W. Australian Mineralogist, 1 (32), 215-216.
Plimer, I.R. (1983) Green titanite from Thorndale, via Broken Hill, N.S.W. Australian Mineralogist, 1 (41), 232-233.
Plimer, I.R., and Blucher, I.D. (1979) Unusual phosphate minerals from Wilson’s Pegmatite, Thackaringa, N.S.W. Australian Mineralogist, 1 (24), 113-213.
Pring, A. (1987) Large phosgenite crystals from Broken Hill, N.S.W. Australian Mineralogist, 2 (1), 25-26.
Segnit, E.R. (1946) Barium-feldspars from Broken Hill, New South Wales. Mineralogical Magazine, 27, 166-174.
By Peter Andersen
P.O. Box 2418
Mildura
Victoria 3502
Australia
Email: pjandersen50@hotmail.com
It is pretty well understood that everyone who collects minerals knows that the main Broken Hill lode is one of the great mineralogical rainforests of the world with almost 300 different mineral species being recognized as occurring there. What very few mineral collectors also realize is that there is also a wealth of minerals found in various deposits within a 100 kilometre radius around the main township of Broken Hill (see Figure 1). These deposits could be small isolated occurrences such as the deposit of the rare barium feldspars found at the local piggery to large commercially viable deposits that were once mined many years ago and in some cases are still being mined even today. Even the highly metamorphosed Precambrian rocks that make up the hills around Broken Hill are full of many examples of well crystallised and often quite showy minerals. One example that comes to mind is the very large individual crystals of almandine, up to 30 cm in size, that occur in some of the local chlorite schists as a result of retrograde metamorphism that occurred in the Willyama Complex around 500 million years ago.
The mineral occurrences that occur within the Broken Hill region can basically be summed up as being:
1/ The main Broken Hill lode orebody that has now been continually mined for over a century.
2/ Smaller outlying orebodies that once were of economic importance. Some such as the orebody known as the Pinnacles Mine were even re-established as an operation and commercially worked this century. There are three recognized types of these smaller outlying orebodies and they are:
Broken Hill type deposits which occur in a characteristic sequence of high grade metamorphic rocks. These rock units include gneisses, amphibolite and small banded iron formations. The ore mineralisation of Broken Hill type deposits occur in narrow units of the ore horizon which are parallel to the layering of the enclosing sillimanite rich and quartz rich gneisses. The primary ore mineralisation of these lodes was formed at the same time as the enclosing original sedimentary and volcanic rocks and therefore underwent the same high temperatures and pressures of metamorphism that this region has been subjected to over the geological time from original deposition to present day. Broken Hill type deposits are characterised by the minerals galena, sphalerite, chalcopyrite, pyrrhotite, quartz (which is coloured blue due to the stress that the quartz was subjected to during metamorphism), spessartine, rhodonite, gahnite and a high lead bearing orthoclase that is coloured green. Examples of Broken Hill type deposits include the Pinnacles Mine, the Postosi Open Pit, the Parnell Mine, the Southern Cross Mine, the Melbourne Rockwell Mine and the Nine Mile Mine.
Thackaringa type deposits which occur in a characteristic sequence of lower grade metamorphic rocks when compared to the metamorphic rocks that the Broken Hill type deposits occur in. A major characteristic of Thackaringa type deposits is that the ore minerals occurred in narrow quartz-siderite veins which cross cut the layering of the enclosing rocks. These deposits are very common in shear and fault zones and their mineralogy is rather simple when compared to that of the Broken Hill type deposits. Most of the Thackaringa type deposits were restricted to the western and northern parts of the Willyama Complex and they were formed later than the enclosing metamorphic rocks. The veins that make up the Thackaringa type deposits occur in retrograde shear zones cutting across the retrograde schistosity (Barnes, 1980). Because the Thackaringa type deposits were formed later than the metamorphic rocks that enclose these orebodies it is generally believed that they originated as a result of the preferential sweating out of base metals, such as lead and silver, from the surrounding Broken Hill type deposits during the closing stages of the high grade metamorphic epogenic processes (Plimmer, 1977). The ore mineralogy of the Thackaringa type deposits includes galena, chalcopyrite, pyrite and tetrahedrite. In these deposits sphalerite is notably absent or else it is a very minor constituent and the galena is quite argentiferous. There are no minerals that are quite characteristic of the Broken Hill type deposits, such as the blue quartz, spessartine, rhodonite, gahnite and green orthoclase, present in the Thackaringa type deposits. Due to the extensive weathering of these orebodies, there occurred extensive enriching of silver above the watertable and it was these silver values that made these deposits economically viable as a mining operation. Mining of the Thackaringa type deposits finished once the enriched silver values present in the ore above the watertable had been extracted. Because of this the Thackaringa type deposits had a very short mining history and a shallow depth of operation. Examples of Thackaringa type deposits include the mines that worked the orebodies around the settlements of Thackaringa and Silverton.
Other heavy and base metal mineralization deposits which include the gold deposits of the Mulculca area near Red Hill in which the gold is in quartz associated with pyrite; the platinum deposits to the east of Broken Hill; the copper deposits of Silverton, where the Umberumberka East Copper Mine produced at least 100 tons of high grade copper ore, and to the south east of Broken Hill where the Copper Blow yielded up some tens of tons of copper ore.
3/ Pegmatite occurrences, some of which were economically viable and are still being worked this century. The economic minerals of these pegmatites included beryl, cassiterite, muscovite and orthoclase. Examples of pegmatite in the Broken Hill region that were worked commercially include the Triple Chance Mine, Egebek Quarry, Gava’s pegmatite, Wilson’s Pegmatite, the Huel Bijerkerno Mine, the Lady Don Mine, the Poolamacca Tin Mine, the Trident Mine and the Yanco Glen deposit which produced a few tonnes of Wolframite ore.
4/ Minerals present in the metamorphic rocks, some of which were once economically viable and have been worked on a commercial basis every now and then. The economic minerals include almandine, sillimanite, kyanite etc. Examples of these commercially worked deposits in the metamorphic rocks include Ireland’s Quarry, O’Connell’s Kyanite Quarry and Mawby and Fishers Quarry
Some of the more notable mines, pegmatites, other deposits and individual localities that are located in the Broken Hill region and which excludes the main Broken Hill orebody (see Figure 1) include:
1/ The Pinnacles Mine
The orebody that occurred in the severe buckle west of the South Pinnacle Hill was named the Pinnacles Mine and it is located 14 kilometres to the south west of the main Broken Hill lode. This orebody has a very similar primary mineralogy to that of the main Broken Hill lode and so has been designated as being a Broken Hill type deposit. The outcrop of this lode was discovered in late1884 by two prospectors, Maiden and Pretty, and to date about 300 000 tonnes of ore has been extracted from this lode and processed for its metal values. The orebody of the Pinnacles Mine is very siliceous and the rather narrow orebodies have been tightly folded. The mineralogy of this mine was very similar to that of the main Broken Hill lode but was not as extensive in the number of different mineral species present in that fabulous deposit. The main primary minerals present in the Pinnacles Mine were galena, gahnite, hedenbergite, loellingite, green orthoclase, pyrrhotite, quartz, spessartine, sphalerite and tephroite. There was also a limited oxidised zone that produced small amounts of azurite, cerussite, malachite, and pyromorphite. The mine has change hands a number of times and even in the early part of the 21st century this particular mine was being operated as a source of ore by the Consolidated Broken Hill Company. The ore dumps of the Pinnacles Mine became a real bonanza for mineral collectors when 60 000 tonnes of oxidised ore from the Kintore and Block 14 open Cuts was extracted and dumped there for processing at the end of last century by the Consolidated Broken Hill Company that now owned and operated his mine. It was really great that mineral collectors were given access to this ore by the Pinnacles mine operators as it was a superb and accessible source of the fabulous well crystallized and rare minerals that the Broken Hill oxidised zone was famous for producing. In fact a number of species new to Broken Hill were found in the dumped oxidised ore from the Kintore and Block 14 open Cuts, identified and described in time to be added to the mineral descriptions of the 1999 book on the mineralogy of Broken Hill.
2/ Other Broken Hill Type Deposits
There are a number of other orebodies in the Broken Hill district that have mined Broken Hill type deposits as their source of ore. These orebodies include the Potosi Open Pit which is a small deposit located 2 km to the east of Broken Hill and now has the distinction of being a type locality for two mineral species: hoganite and paceite; the Southern Cross Mine and the Parnell Mine which are very close to one another and the Nine Mile Mine that is situated 9 km to the north west of the main Broken Hill lode. The Nine Mile mine has the distinction of being a mine in the Broken Hill district that had no ore raised from its operation, even though a shaft was sunk to a depth of 60 metres and two levels were driven at 25 and 50 metres. This mine was opened in 1887 by a syndicate called the Nine Mile Silver Mining Company and obviously they went broke! Very nice crystals of the zinc spinel member, gahnite, can still be found at this locality. The Melbourne Rockwell Mine, which is located 13 km to the south east of the main Broken Hill township at Little Broken Hill is the type locality for the mineral ecandrewsite and it is also has the distinction of being the only other locality in Broken Hill to have rhodonite present as part of its mineralogy.
3/ The Mines and Economic deposits of Silverton
Silverton is a very small settlement 22 km to the west of the main Broken Hill township. Silverton’s claim to fame is that the mines around this town were being worked for their ore values several years before the discovery of the main Broken Hill lode by the Prussian army deserter that had changed his name from Jerome Freiherr von Pereira to Charles Rasp. Silverton is still an active settlement as it now exists on tourism and it even has the distinction of having being the site for the filming of several feature films. The mines that worked the small lodes around Silverton were all extracting ore from Thackaringa type deposits and there were a number of these. Silver was the main metal being extracted from these mines and a number of silver bearing minerals are to be found occasionally in old collections today. Some of the mines in the Silverton area that were worked for their silver content back in the late 19th century included:
The Umberumberka Mine. This mine worked an orebody that was 5 km to the west of Silverton itself. It was discovered in 1882 and during its short life produced around 20 000 tonnes of high grade silver ore. It was the discovery and establishment of this mine that gave rise to the township of Silverton. The mine reached a depth of 130 metres and there were 7 levels in it to access the rich silver ores. These rich silver ores were made up of silver bearing galena along with silver bearing minerals such as argentite, chlorargyrite, silver and stephanite. Other notable minerals found in this deposit included cerussite, nadorite and the largest crystals of phosgenite (to 5 cm in length-Pring, 1987) found in any of the mines of the Broken Hill district. The silver bearing ores of the Umberumberka Mine occurred in sheared re-metamorphosed rocks which are associated with large bodies of amphibolites and pegmatites.
The Daydream Mine. This mine worked an orebody that was 16 km to the north east of Silverton itself. Its orebody was discovered in 1882 by a prospector named Joe Meech and during its short life produced around 30 000 tonnes of high grade silver ore assaying around 60-600 ounces of silver per ton. The total silver production from this mine was in the vicinity of 96 000 ounces. (Andrews, 1922). The lodes of the Daydream Mine occurred within narrow shear zones at the footwall of granite dykes and the outcrop of this lode was 30m long and varied from 0.5m to 2.5m in width (Leach, 1997).The mine reached a depth of 150 metres and there were a number of shafts sunk and levels driven to access the rich silver ores of this lode. These rich silver ores were made up of silver bearing galena along with silver bearing minerals such as argentite, boleite, chlorargyrite, silver, stephanite and tetrahedrite. Other notable minerals found in this deposit included cerussite, fluorite, malachite, phosgenite and siderite. Like all the other mines that worked the Thackaringa type deposits in the Broken Hill district the Daydream mine had a short history of operation and the company ceased mining operations once the rich silver bearing weathered ore above the water table was extracted and processed. These days the Daydream mine is operated as a tourist attraction and this mine gives its visitors a chance to see how mines operated at the turn of the last century and even go underground through its narrow tunnels.
Other mines in the Silverton district that mined Thackaringa type deposits included the Apollyon Mine, the Hen and Chicken Mine and the Silver King Mine.
A pegmatite 1.5 km from Silverton was named Gava’s Albite pegmatite and operated for some time as a source of albite for high quality ceramics. This pegmatite has intruded and slightly sheared an amphibolite rock and is composed mainly of albite with minor associated muscovite, quartz and beryl. Gava’s Albite pegmatite has the distinction of being the only pegmatite in the Broken Hill district that has actually produced gem quality beryl crystals, but they are no larger than 1 cm in size (Plimmer, 1977).
4/ The Mines, Pegmatites and Metamorphic Minerals of Thackaringa
The Mines of Thackaringa. Thackaringa has the distinction of being the locality where the discovery of the first orebodies in this far western district of New South Wales occurred. It was back in 1876 that Paddy Green (who was living in Menindee at that time) discovered the first lode to be pegged in this region of outback Australia. Numerous prospectors followed and soon a number of mines were being operated in this remote region of New South Wales that had been named Thackaringa and was located 35km to the south west of what would soon become the main regional town of Broken Hill. A small township grew up around the discovery of these small silver rich orebodies and there was even a school along with the numerous “hotels” (which were really just basic watering holes for the many miners) that always seems to sprout around a group of mines when they come into existence. Nowadays there is no sign whatsoever that here once existed at Thackaringa a thriving small community except for the large number of shafts that are still there. The main mine at Thackaringa was the Pioneer Mine which operated from around 1884 through to 1925 and reached a total depth of 150 metres. Other mines in this district included the Gipsy Girl but the depth of its main shaft was only 70 metres and it had ceased ore production by 1892; the Lily Mine, the Homeward Bound Mine, the Thackaringa Mine, The Gipsy boy Mine, Gipsy Queen Mine, Lady Brassey Mine and the Hercules Mine. In all 27 named mines are recorded but production records are fragmental. The total ore produced from all of the Thackaringa mines was only around 30 000 tonnes and most of this ore production appears to have come from two mines: The Pioneer Mine records show that it produced 20 000 tonnes of ore and the Gipsy Girl Mine records show that it produced 10 000 tonnes of ore. All of the operating mines at Thackaringa were extracting silver bearing ore from Thackaringa type deposits, which at Thackaringa were vein type deposits located within the Thackaringa-Pinnacles Shear Zone. In the Thackaringa deposits the primary ore minerals, mainly made up of argentiferous galena, arsenopyrite, chalcopyrite, covellite, cubanite, gersdorfite, lollingite, marcasite, pyrite pyrrhotite, sphalerite, tetrahedrite and valleriite, were located within narrow steeply-dipping quartz siderite veins. Siderite also made up the core of the vein as well. The margin of these siderite veins was composed mainly of quartz, chalcopyrite, pyrite and minor sphalerite. Oxidation of the primary ore minerals resulted in the formation of extensive deposits of supergene minerals, such as chlorargyrite, which was the main source of the silver that was being produced from these mines.
The veins of the Thackaringa lead silver mines varied in width from a few inches (about 5 cm) up to 3 or more feet (1 or more metres) and typical descriptions of good ore produced by a number of these mines (taken directly from King, 1953b) are:
Lily Mine-vein 6 to 12 in. wide, cerargyrite with earthy malachite, 18 tons bagged, assaying 520 oz. Ag per ton and 26% Pb.
Gipsy Girl-4 to 14 in. of galena with 2ft. of iron ore (siderite or limonite) and quartz beneath. The ore yields 50 oz. Ag per ton and 72% Pb.
Pioneer-assays ranged from 56% Pb, 40 oz. Ag per ton, to 25% Pb, 12 oz. Ag per ton. Ore 6 ft wide in places.
Homeward Bound-ore 30 to 42 in. wide, one “small” parcel 40oz. Ag per ton, 1 oz. Au per ton, 60% Pb.
Hercules-200 tons shipped, assaying 40 oz. to 80 oz. Ag per ton, 50% to 70% Pb.
The Pegmatites of Thackaringa. As well as the numerous mines that worked the Thackaringa type deposits there were also a number of pegmatites that were of commercial viability. The best known pegmatite at Thackaringa is the Triple Chance Mine that was operated for many years by a real hardy soul by the name of Mrs Tess Alfonzi. This locality produced 37 000 tonnes of feldspar, 3000 tonnes of quartz, 350 tonnes of beryl and 184 tonnes of muscovite. The late Mrs Tess Alfonzi was very proud of the fact that beryllium extracted from Triple Chance Mine beryl was used in the Apollo 11 Luner Lander and so had been to the moon. The mineral lease of the Triple Chance Mine has once again been taken up and commercial mining of its economic minerals has once more been undertaken at this deposit. Other pegmatites that have been commercially operated in the Thackaringa region included the Egebek Quarry; Lady Beryl; Wilson’s Pegamatite (which was operated by Johnny Wilson as a source of feldspar and this pegmatite contained quite rare primary phosphate minerals that included barbosalite, cyrilovite, triplite and wolfeite (Plimer, 1979). Other collector quality minerals that were present in this pegmatite include beryl, bertrandite, muscovite, quartz, and possibly the best crystals of microcline from an Australian locality that were collected by the author in 1983); Baker’s Pegmatite (this was a source of the rare mineral davidite) and an unnamed deposit near the intercontinental railway line that mined very large crystals of annite formed in a pegmatite near the edge of the Thackaringa-Pinnacles Shear Zone.
The Metamorphics of Thackaringa. There have been a number of commercial mining operations established to extract minerals from the metamorphic rocks around Thackaringa. These include O’Connell’s Kyanite Quarry that was established 12 km to the south west of Broken Hill to mine refractory grade kyanite; Mawby and Fisher’s Quarry that was established to mine a pod of sillimanite and this quarry also produced nice crystals of diaspore, corundum and clinozoisite as well; Ireland’s quarry that was established to mine almandine crystals in a chlorite schist for the abrasive industry. Ireland’s Quarry is located 25 km to the south west of Broken Hill within a large shear zone called the Thackaringa-Pinnacles Shear Zone in which the high grade metamorphic gneissic rocks have been re-metamorphosed into lower grade almandine-chlorite schists. Such re-metamorphism of higher grade metamorphic rocks into metamorphic rocks of a lower grade is called retrograde metamorphism and the individual almandine crystals formed in these schists grow to incredible sizes and the almandine crystals from Ireland’s Quarry certainly confirm this as they can be up to 30 cm in size. This retrograde metamorphism occurred around 500 million years ago and the Thackaringa-Pinnacles Shear Zone is the principal zone of re-metamorphism in the Broken Hill district. Other localities in the Thackaringa region that have produced mineral specimens include the Repeater Station, Belle View, Big Hill, Peak Hill and the Twenty Mile Sillimanite Pit. The minerals found in the metamorphic rocks at these localities include almandine, annite, corundum, epidote, ilmenite, kyanite, magnetite, magnesite, rutile, schorl, sillimanite, staurolite, titanite, etc.
5/ The Euriowie Pegmatites
Euriowie is now an abandoned settlement that was once established 80 km north east of Broken Hill. In 1884 commercial amounts of tin were discovered in a number of pegmatites in a remote region of western New South Wales which was to be then named Eurowie. This discovery of commercial amounts of tin led to the establishment of the Euriowie township, which was a small settlement that once had 700 people, two banks, three stores, four hotels, several whorehouses and a racecourse. The greatest mining activity was around the turn of last century and by 1910 most of the rich tin ore had been extracted from all of the pegmatites in the area and this resulted in the township of Euriowie being abandoned. The largest mine at Euriowie was the Huel Byjerkerno Mine and other mines of this region included the Lady Don Mine, the Poolamacca Tin Mine, the Trident Mine, and quite a few others as there were over 800 leases pegged in this district at one time. The minerals that were present in these tin bearing pegmatites included albite, amblygonite, augelite, beryl (caesium rich), cassiterite, columbite, corundum, elbaite, fluorapatite, fluorite, lazurite, lepidolite, morenite, muscovite, paragonite, petalite, quartz, rutile, schorl, svanbergite, tantalite, topaz, etc. There have also been small amounts of azurite, cuprite, malachite and pyrrhotite found in the pegmatites of this area as well.
6/ The Platinum Group Mineral Deposits
(iv) 20 km to the east of Broken Hill there are a number of small ore deposits that have been extensively oxidised and contained in the gossans of these deposits is a number of very rare platinum group minerals that are only present as minsicule grains. These gossan deposits containing these platinum group minerals are present at Mulga Springs, Little Darling Creek, Round Hill (Moorkaie Hill) and Red Hill. The platinum group minerals that have been identified to date include platinum alloys such as braggite, sperrylite and native platinum; and palladium alloys such as froodite, mertiete II, paolovite and a number of unnamed phases of palladium-copper-bismuth-mercury and telleurium alloys. There are also secondary base metal minerals present in all of these gossans including anglesite, azurite, barite, cerussite, chalcocite, chrysocolla, iodargyrite (the only known occurrence of this mineral in the Broken Hill district outside of the main Broken Hill lode) and malachite. Primary minerals found in these gossans include arsenopyrite, bismuth, gold, galena, ilmenite, pentlandite and pyrite.
7/ Other Localities
A number of other localities exist in the Broken Hill district that have produced unusual minerals or well crystallised specimens. These include:
(i) Thorndale Station which is located 30 km to the east of Broken Hill and it is here that gem quality crystals of lime green titanite have been collected from a coarse grained clinopyroxene-amphibole-plagioclase mafic granulite. This mafic granulite has been partially replaced by a retrograde assemblage consisting of calcite, amphibole and titanite (Plimmer 1983). These gem quality titanite crystals are up to 0.5cm across and are present in transgressive white calcite veinlets that are around 1 cm in width.
(ii) McDougalls Well, located 80 km to the north of Broken Hill and is accessed via Corona Station, is the premier locality in New South Wales for amethyst. The amethyst, smoky and other types of quartz occurs here as veins in schists and slates of the Torrowangee Group of metamorphic rocks. The quartz crystals at this deposit were formed during the metamorphism that happened to these rocks 500 million years ago and they can be found here in a range of colours that includes purple (amethyst), black (smoky), green (this colour being caused by the long period of exposure to sunlight of the purple crystals - Plimer, 1977) and colourless. These quartz specimens are very attractive and can still be collected today.
The Piggery, which is located near the abattoirs in Ryan Street, and the Waterworks Hill outcrops of rare barium feldspar minerals was originally described by Sir Douglas Mawson and both of these localities are within the suburban confines of the Broken Hill township. These feldspars occur as small light-coloured masses within a coarse grained granite gneiss and the barium feldspar group mineral species identified from here include armenite, celsian and hyalophane.
In the southwest corner of the Broken Hill Racecourse there was a small pegmatite outcrop that had a shaft sunk on it for the purpose of extracting commercial amounts of whatever minerals could be found. The mineral collection of the Museum Victoria has three specimens in its collections from this pegmatite and they are manganocolumbite and goethite and these two speciemns were originally in the mineral collection of Sir Maurice Mawby and they came into the museum’s mineral collection when that Augustus person donated his personal mineral collection to the museum back in 1977 just before he croaked.
The mineral collection of the Museum Victoria has possibly the world’s biggest collection of minerals from the Broken Hill district of New South Wales with a holding of over 3500 specimens. Some of the more obscure localities that they have represented by having mineral specimens from these localities being registered in this collection include Clondes Property, Great Western Mine, Hinspeter Mine, Huonville Station, Kantappa Tin Mine, Maybell, Mayflower Mine, Mount Gipps, Mount Rutland, Mulga Springs, Parramoota (this locality is a misspelt Purnamoota- see Figure 5), Rockwell Paddock, Sterling Vale (misspelling for Stirling Vale- see Figure 5), Thompsons Tank and Waukeroo Tin Field.
The Minerals from the slags of Broken Hill. In order to process the ore that it was mining from its leases on the Broken Hill lode, the Broken Hill Proprietary Company ended up erecting on its leases 15 smelters before the end of the 19th century. Other mines which also had smelters to process the ore that was extracted from their mining operations included the British Mine, the Block 14 Mine, the Central Mine and the South Mine. By the time that the ore smelting operations had finished for good in Broken Hill, which was in 1898, there were an estimated 800 000 tonnes of slag dumped on a number of the mining leases. Over the next 100+ years these slags would undergo secondary alteration due to normal weathering processes and this resulted in the growth of a number of secondary mineral species within the gas bubbles of the slags. These secondary minerals that had now been formed in these slag gas bubbles were subjected to a scientific study by the very advanced amateur mineralogist, Peter Elliot, and he published his results in the 1997 special Broken Hill issue of the Australian Journal of Mineralogy. Peter Elliot’s study of these minerals resulted in the following species being identified as occurring in the slag deposits of Broken Hill: anglesite, aragonite, bechererite, brochantite, calcite, caledonite, cerussite, connellite, cumengite, cuprite, gypsum, hydrozincite, jarosite, ktenasite, lanarkite, leadhillite, linarite, malachite, namuwite, plumbojarosite, posnjakite, schulenbergite, serpierite, sulphur and several unknowns. The IMA Commission on New Minerals and Mineral names has ruled that chemical compounds formed by the actions of geological processes on anthropogenic (man made) substances, such as slags, will not be considered as being valid mineral species (Nickel, 1995).
Below is an alphabetical listing of as many different mineral species that the Author knows to occur in the Broken Hill district. This list not only includes the well known mineral species from the main Broken Hill orebody but also as many different species that the author has been able to track down from other localities within a 100 km radius of the main Broken Hill township. I am aware that this list is not completely exhaustive in the listing of all species known to occur in the Broken Hill district but it is a start and it is a good basis for anyone that is interested in the range of minerals already recorded from this incredible mining district. The following abbreviations have been used in this table to delineate where the minerals occur in the district of Broken Hill:
1/ MLOZ= main lode-oxidised zone
2/ MLSZ= main lode-supergene zone
2/ MLPO= main lode-primary ore zone
3/ MLCR=main lode-country rocks
4/ CML= the lode of the ABH Consols mine
5/ OLOZ= other lodes-oxidised zone
6/ OLPO= other lodes-primary ore zone
7/ M= occurrences in the Broken Hill metamorphic rocks
8/ P= occurrences in the Broken Hill pegmatites
9/ I= occurrences in altered Intruded ultramafic bodies.
10/ S= post mining minerals found in slags from the smelting processes of the various mines.
Where possible I have also indicated in the very last column some of the names of the main mines, commercial operations and interesting localities that have produced these various minerals. I have also included some comments about some of the post mine minerals in this column as well when they are relevant. Minerals in capital letters only are those that were first described and named from the district of Broken Hill. Those minerals listed in small letters are those that have been described by previous mineralogists but there is an actual need of confirmation of identity by chemical analysis or X-ray diffraction and also many of the secondary slag minerals have been listed this way as well since the IMA Commission on New Minerals and Mineral names does not consider these type of minerals as being a valid species. There are some unknown species that are listed that still needs work done on them to confirm their mineral identity. In these cases there just is not enough of these minerals available at present to be able to go any further with their identification.
ACKNOWLEDGEMENTS
I would like to acknowledge the help that the Dr Bill Birch (the senior curator) and Dermot Henry (collection manager) of the Museum Victoria’s Department of Mineralogy gave in allowing me to access their data base and print off the records that I needed. These records have been invaluable in compiling the data table of the minerals of the Broken Hill district.
BIBLIOGRAPHY
Andrews, E.C. (1922a) The Geology of the Broken Hill District. Memoirs of the Geological Survey of New South Wales 8, Sydney, Australia, 257 p.
Andrews, E.C. (1922b) Notes on the geology of the Broken Hill district. Economic Geology, 17, 470-490.
Barnes, R.G. (1980) Types of mineralization in the Broken Hill Block and their relationship to stratigraphy. In: Stevens, B.P.J. (Editor) A Guide to the stratigraphy and mineralisation of the Broken Hill Block, New South Wales. Records of the Geological Survey of New South Wales, 59-60.
Birch, W.D. (1999) The minerals. In: Birch, W.D. (Editor) Minerals of brokenhill. Broken Hill City Council in conjunction with Museum Victoria, Melbourne, Victoria, Australia, 90-262.
Birch, W.D, (Editor-1999) Minerals of brokenhill. Broken Hill City Council in conjunction with Museum Victoria, Melbourne, Victoria, Australia, 289 p.
Bosworth, J. (2002) What’s new in Australia. Australian Journal of Mineralogy, 8 (2), 80-81.
Day, B. (1998) What’s New in Australia. Australian Journal of Mineralogy, 4 (1), 40-41.
Elliot, P. (1997) Minerals of the Slags from Broken Hill, New South Wales. Australian Journal of Mineralogy, 3 (1), 77-83.
Elliot, P., Brugger, J., Pring, A., Cole, M.L., Willis, A.C., and Kolitsch, U., (2008) Birchite, a new mineral from Broken Hill, New South Wales, Australia: description and structure refinement. American Mineralogist 93, 910-917.
Elvy, S.B., Gray, N.D., McAndrew, J., Williams, P.A., and French, D.R. (1998) Platinum group minerals from the Broken Hill district, New South Wales. Australian Journal of Mineralogy, 4 (1), 33-39.
Johnson, J. E. (1956a) Specimen minerals of the Egebek pegmatites, near Broken Hill. The Australian Amateur Mineralogist, March 1956, 5-7.
Johnson, J. E. (1956b) Further notes on the specimen minerals of the Egebek Ming Field, Broken Hill. The Australian Amateur Mineralogist December 1956, 101-102.
King, H.F. (1953a) The Pinnacles Mine and its environment. In: Edwards, A.B. (Editor) Geology of Australian Ore Deposits. Australasian Institute of Mining and Metallurgy, Melbourne, Victoria, Australia, 677-684.
King, H.F. (1953b) The Thackaringa Mines. In: Edwards, A.B. (Editor) Geology of Australian Ore Deposits. Australasian Institute of Mining and Metallurgy, Melbourne, Victoria, Australia, 685-686.
King, H.F., and Thomson, B.P. (1953) The geology of the Broken Hill district. In: Edwards, A.B.(Editor) Geology of Australian Ore Deposits, Australasian Institute of Mining and Metallurgy, Melbourne, Victoria, Australia, 533-577.
Lawrence, L.J. (1967) Mineralogy and textures of Thackaringa sulphide ores. Proceedings of the Australasian Institute of Mining and Metallurgy, 222, 85-94.
Lawrence, L.J., Ramsden, A.R., and Graham, I.T. (1999) On the Oxidation of Dyscrasite and associated Minerals of the Consols Lode, Broken Hill, New South Wales. Australian Journal of Mineralogy, 5 (2), 63-68.
Leach, J.D. (1997) The Daydream Mine, Silverton, New South Wales. Australian Journal of Mineralogy, 3 (2), 103-109.
Lewis, B.R., Forwood, P.S., and Roberts, J.B. (1965) Geology of the Broken Hill lode reinterpreted. In: McAndrew, J. (Editor) Geology of Australian Ore Deposits, Volume 1, Proceedings of the 8th Commonwealth Mining and Metallurgy Congress. Australasian Institute of Mining and Metallurgy, Melbourne, Victoria, Australia, 319-332.
Lishmund, S. R. (1982) Non-metallic and tin deposits of the Broken Hill district. Geological Survey of New South Wales, Bulletin 28, 176p. Department of Mineral Resources, Sydney, Australia, pub.
Mawby, M. (1975) The Contribution of Broken Hill, N.S.W. Australian Mineralogist, 1 (1), 1.
Nickel, E.H. (1995) Definition of a Mineral. The Mineralogical Record, 26, 437-438.
Plimer, I.R. (1977) Mineral Collecting Localities of the Broken Hill district. Peacock Publications, Hyde Park, South Australia, Australia, 65p.
Plimer, I.R. (1981) Notes for the 1981 Mineralogical Society of Victoria’s excursion to Broken Hill. Unpublished but distributed to all members that participated on this excursion.
Plimer, I.R. (1982) Corundum-bearing schist from the Willyama Complex, Thackaringa, N.S.W. Australian Mineralogist, 1 (32), 215-216.
Plimer, I.R. (1983) Green titanite from Thorndale, via Broken Hill, N.S.W. Australian Mineralogist, 1 (41), 232-233.
Plimer, I.R., and Blucher, I.D. (1979) Unusual phosphate minerals from Wilson’s Pegmatite, Thackaringa, N.S.W. Australian Mineralogist, 1 (24), 113-213.
Pring, A. (1987) Large phosgenite crystals from Broken Hill, N.S.W. Australian Mineralogist, 2 (1), 25-26.
Segnit, E.R. (1946) Barium-feldspars from Broken Hill, New South Wales. Mineralogical Magazine, 27, 166-174.
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MINERAL SPECIES FROM BROKEN HILL, NEW SOUTH WALES AND ITS OUTLYING REGIONS
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