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Wednesday, 16 September 2015

THE GULF FLUORITE MINE NEAR EMMAVILLE, NEW ENGLAND DISTRICT NSW AUSTRALIA


THE GULF FLUORITE MINE NEAR EMMAVILLE, NEW ENGLAND DISTRICT NSW AUSTRALIA

The Gulf Fluorite specimen 100mmX53mm Clifford Collection
Fluorite (calcium fluoride, Ca F₂), also called fluorspar) is found in many places in New England, but the area north-west of Emmaville, near the margin of the Mole Granite, known as The Gulf appears to be the place where there are the most reported occurrences. Of all of these, only that commonly called The Gulf Fluorite Mine (alternatively known as Shepherdly’s Mine or Shepherdly’s Fluorite Mine) came even close to being an economic source of the mineral.
There are a number of newspaper reports from February 1919 in Trove, near enough to identical and probably copied from a press release.
Most geological information also comes from this time as investigations were made into the economic possibilities of the mine. The remote location and the limited amount of mineral available soon led to its abandonment. However, the variety of minerals to be found there has made it a popular collecting locality over the years, so whenever access is possible (it is private property, so keep away at other times) there are always quite a few people keen to make the trip.
Minerals found at the Gulf Fluorite Mine
Field trips associated with Minerama (Glen Innes) and Gemfest (Emmaville) are the most likely ones that you can go on, so check out their websites for information (Google them and you will soon find them).
I have visited the place only once, in preparation for the 1997 Minerama field trip and the theme booklet on fluorite which appeared that year. You will find a copy of the book in this Blog (February 2024). We had quite a few problems with the book in 1997. Most of the colour plates are unsatisfactory and, to make matters worse, they aren’t all on the pages shown in the table of contents. Not only that, but I lost my copies of the original photos when I had
Heide Klingbeil and John Paix examining a chlorite specimen
computer problems in 2014. My most abiding memory of that reconnaissance is the large number of needle-like pale green beryl crystals scattered on the dumps. Hopefully there are still some left for present-day collectors!
In spite of these defects, the content was good and I have copied the section dealing with The Gulf Fluorite Mine into this blog. Here it is, with a description of the references if you wish to consult them. I have made a few very minor corrections to the original text.

The only deposit in New England which produced fluorite on anything approaching a commercial scale is that at the Fluorite Mine, otherwise known as Shepherdly's Fluorite Mine. It is on ML
Mine locations at The Gulf (from the Mole Tableland map)
10, 22km northwest of Emmaville, Parish Muir, County Gough; GR 44783735, Inverell 1:250,000.
The mineralization at the Fluorite Mine occurs as small lenticular shoots in "shrinkage" veins in a coarse-grained granite. These were called "pipes and vughs in the granite" by Raggatt.
Reference 28, p 13. “The lode strikes 285⁰ and has an average width of 0.6m.The vein is made up largely of fluorite, sometimes in large masses (up to 0.6m of pure fluorite in places) with abundant quartz, feldspar, chlorite and greisen. Sulfides of arsenic, copper and zinc and a little beryl are the main accessory minerals. This deposit has been worked in the past for wolframite and fluorite. One main shaft was sunk in 1919 following a fluorite-rich ore shoot, 2m in diameter, which pitched steeply to the west. Another shaft 3m deep was sunk on fluorite 24m to the west of the old shaft. A sample of several tonnes of hand-picked ore contained 93.1% CaF₂. The fluorite is commonly extracted in large, bright-green masses, free from impurities. Both the fluorite and wolframite are very pure and the fluorite could be used for enamelling purposes. The remoteness of this deposit and the small reserves of ore make further production unlikely…. Total recorded production is 296 tonnes of which 203 tonnes were produced in 1919.”
Reference 25 p 372. "Fluorite has been won from what may be a pegmatitic vein or shoot in the
Cover photo from the 1997 Minerama book
granite…. It strikes at 105⁰. M, and is 0.6m wide along drives and 2m in diameter in a shoot which pitches steeply westerly..... It is of interest that the prolonged exposure to the atmosphere of fluorite on the dumps has resulted in a loss of colour
."
Smith (Reference 29 p 76) also refers to the Fluorite Mine. "There are several localities in which the fluorite is found of the same quality. It is sometimes roughly crystallised, very translucent, and always of a rich green colour, except when associated with the copper ore, when it is less distinct in colour. The locality in which it is found is about three-quarters of a mile west to 3 miles north-west of the Gulf. ... Several inquiries were recently made for pure fluorite for purposes for which inferior material would be unsuitable, and as samples had  been forwarded to Mr. Card (Ed. - the N.S.W. Government Analyst), inquiries were readily satisfied as to quality. This has resulted in the mining of considerable quantity - over 100 tons - and the establishment of the enamelling industry in Sydney."

Front cover specimen with fluorite necklace
According to David (Reference 11 p 111), “Gaden's Lode, the furthest west of the above-mentioned lodes (Ed. - the Gulf Lodes) is situated in portion 33, parish Muir, county Gough. The vein is from 2 to 3 feet wide, and strikes 40⁰ east of north and west of south, dipping about 82⁰ south-easterly. Veinstone chlorite and quartz with vughs filled with purple fluorspar. The walls are not defined, the veinstone merging into a very quartzose ternary granite, becoming less quartzose at a distance from the vein."
Reference 10 p 54. “Davison's Lode. West of Gulf Creek, Parish Muir, County Gough. Strike N.E. Shaft sunk about 20 feet in chloritic quartzose lodestuff containing wolfram, copper pyrites and fluorspar."
Reference 10 p 59. “Hutton's Wolfram Lode. West of Gulf Creek, The Gulf, Parish Muir, County Gough. Strike N. 60⁰h E. Opened for a length of about 4 chains. Fluorspar conspicuous, also chalcopyrite. Occurs in chloritic veinstone with crystalline quartz in vughs and small veins. Width from a thread to 2 feet. The Gulf Stream Lode. (Portion 60, Parish Land’s End, County Gough; GR 450374, Inverell 1:250,000) is a fissure vein up to 2m wide, but averaging 0.6m. It was worked for tin. Like the other lodes in The Gulf district, fluorite and wolframite are both present in the vein, which consists mostly of quartz, chlorite and decomposed felspar. Balmain and Rumsby’s mine is located at GR 44883721, Inverell 1:250,000.”
Reference 25 p 372 states that "Minerals present in the lode include major chalcopyrite with wolframite and pyrite, and minor arsenopyrite, scheelite, galena, beryl, fluorite and tourmaline."
Reference 10 p 66.”Rumsby's Lode, south-west of the Yankee Tin Lodes, The Gulf, Parish Muir, County Gough. ... The pipe measured 10 feet by 8 feet in its strongest part. The veinstone is chloritic and soft. The wolfram occurred in masses of great purity, accompanied by large bunches of rich green fluorspar, and lesser quantities of mispickel and copper pyrites."
Garths Lode (ML 4 in Portion 11, parish Flagstone, County Gough; GR 45833706, Grafton 1:250,000) is a complex and interesting ore deposit. Reference 23 p 15 states that it is "a fissure lode about 1m wide in granite about 50m from the sedimentary contact.  Cassiterite, biotite, chlorite, ferberite, chalcopyrite, arsenopyrite, tourmaline, monazite, topaz, quartz, green and purple fluorite, and torbernite are present. The deposit was worked for tin."
Reference 25 p 371. “Garth's or Gayden's lode consists of the usual quartz-chlorite with cassiterite,
Specimen from The Gulf with fluorite carvings
chalcopyrite, minor green fluorite and rare monazite and torbernite. Strike is 013⁰, dip is near vertical, known length is 200m, and average width is 0.75m. Heisers Lode (ML 68 in Portion 11, Parish Flagstones, County Gough; GR 458370, Grafton 1:250,000) is a greisenous lode adjacent to Garth's Lode. According to Reference 23 it "is developed within siliceous granite at the granite/metasediment contact. Cassiterite, ferberite and pyrite occur in a gangue made up of quartz, chlorite, chrysocolla, stilbite, biotite, magnetite, tourmaline and fluorite, with traces of torbernite. This lode was mainly worked for tin
."
10. (1912). The Tungsten Mining Industry in New South Wales. Miner. Resour. geol. Surv. N.S.W.15 102 pp.
11. DAVID T.W.E. (1887). Geology of the Vegetable Creek Tin-Mining Field, New England District New South Wales. Mem. geol. Surv. N.S.W., Geol. 1 169 pp.
25. MARKHAM N.L. and BASDEN H. (Editors) (1974). The Mineral Deposits of New South Wales. Geol. Survey of N.S.W. 682 pp.
28. RAGGATT H.G. (1924). Asbestos, Emery, Fluorspar, Fuller's earth, Graphite, Phosphates, Talc and Soapstone. Bull. geol. Surv. N.S.W. 14.
29. SMITH G. (1919). The Occurrence of pure fluorspar in New South Wales. A. Rep. Dep. Mines N.S.W. for 1918.
There is more recent material in the various metallogenic maps and surveys (Mole Tableland, Inverell and Grafton) which would help you to locate the above mentioned sites and others mines and prospects in the vicinity. These are all downloadable from DIGS, as are the references listed above.
Happy collecting! It would be of benefit to all future readers of this blog if you could add a comment telling of your collecting experiences at this interesting old mining locality.
Mindat record of the Gulf Fluorite Mine here
Geological Survey of NSW report on Fluorite (1973) here.

Monday, 13 July 2015

CASSITERITE CRYSTALS FROM ELSMORE HILL NEAR INVERELL NSW AUSTRALIA

CASSITERITE CRYSTALS FROM ELSMORE HILL NEAR INVERELL NSW AUSTRALIA
Photo from ALF
A recently reactivated thread on the Australian Lapidary Forum (ALF) about a well-known mineral hunting locality near Inverell, in the New England region of NSW Australia, should remind us all of how precarious our access to collecting localities really is. Read the thread here. Follow it and if a petition is commenced, be sure to add your name to it. It would be a good idea to get involved with the Forum if you aren’t already.
There is a wealth of information available on this locality. I’ve gathered together a number of photographs from some of these and assembled them, into a You Tube slide show, which you will find here. Not only is Elsmore the site of one of the earliest 
Photograph from Minerama book "Cassiterite"
payable alluvial tin deposits in Australia (1871), but it has (in more recent years) become the source of some of the most superb cassiterite crystal specimens in the world. A search on eBay will show that they are in great demand. Until recently, access to the fossicking spot had been made legally possible in an unusual way. The local Inverell Lapidary Club has held a mining lease over the area for the use of its members. By becoming a member of the Club, visitors could legally fossick there. I imagine that the revenue raised has been used to defray the cost of maintaining the mining lease.
What has caused the Club to surrender its lease I cannot say. It may be that income was falling behind expenses or perhaps that the Club has an aging membership (as many lapidary clubs do) and continuing to provide this service simply became a burden. It could be that changes in the mining law are making it difficult for smaller operators to stay in business. Whatever the reason, follow the ALF thread for more information.
Here are some useful references for you to follow up. As you read you will discover that cassiterite and quartz are only two of the many mineral species which have been found at Elsmore Hill.
The first few are to be found in the DIGS data base and can easily be downloaded. The most comprehensive reference is: Geological Survey Report 45 (1966): The Geology and Tin Deposits of the Elsmore Area. The DIGS reference is R00050621. Related to this document, and incorporating much of it, is Elsmore Tin Mine, Inverell which incorporated material from mine records 1934-1981 (DIGS R00046476).
Diggings on the lease
You will discover that the basic geology consists of granite intruding Palaeozoic sediments, overlain by Tertiary basalt. The primary cassiterite deposits are associated with the granite intrusion. Secondary deposits include modern alluvial material and, in particular, “deep leads” – older alluvial material lying beneath the basalt. Much of the prospecting in the area has been (and still is) directed to locating payable wash in these concealed leads. The classic geological map is “Geological Map of the Tin-bearing district around Tingha, Stannifer and Elsmore” by Carne and Pittman (1910). (DIGS R00030525). There is a lot more recent material available also (Inverell metallogenic study) but these should help you to understand what the place is all about.
A search through DIGS shows that there many other reports available from this source. One is Partial relinquishment report EL7177 Elsmore 2011 Malachite Resources (DIGS RE0001817), which is quite recent. The article in Mindat includes further photographs, mineral lists and references here.


Tin Sluicing at Elsmore

Tuesday, 23 June 2015

ALLUVIAL DIAMOND MINING IN THE NEW ENGLAND REGION OF NSW AUSTRALIA

ALLUVIAL DIAMOND MINING IN THE NEW ENGLAND REGION OF NSW AUSTRALIA
 
Most gem hunters seem to be unaware that diamonds have been mined in NSW (off and on) since the gold rush days in the middle of the 19th century. The list of places where at least one diamond has been found is very extensive and I suspect that it would be much longer if the old time miners had not suffered from tunnel vision. “If it’s not gold (or tin) we’re not interested in it. Chuck it out.”
Only at Bingara and Copeton (formerly called Boggy Camp, south of Inverell) were the workings extensive and even then they could hardly have been very profitable. Both places were being prospected for gold or tin when “these funny looking stones” turned up. Sufficient curiosity was aroused for specimens to be sent off for identification and minor rushes followed.
Subsequent searches for primary deposits (like those now being mined in Western Australia) have not met with much success, despite the fact that the diamonds had to reach the Earth’s surface somewhere. From the gem hunting point of view, this is probably a good thing, as modern diamond mining is very big business and casual fossickers are most unwelcome in the vicinity.
Your only real source of accurate information is in the records of the Geological Survey and the Mines Department of NSW. I have mentioned DIGS on numerous occasions, but it is a website that anyone with an interest in things geological needs to get to know. You will have to search Google to locate it. Make sure you bookmark it or put it into your Favourites, if that’s what your web browser does. Click on “Search DIGS” enter “diamond” in the Subject Terms/Keyword box, press “Search” and you will be confronted with a list of 1000 records.  If this seems somewhat overwhelming, try putting in a locality (eg Copeton). This reduces the 1000 to 94, a much more manageable number if you want to start researching. It’s a series of logical steps to bring up a document on your screen, where you can read it, save it or delete it as you please. Note the size of the document before you commit yourself to waiting for it for maybe half an hour.
If you want a short cut to a few interesting documents, just copy these numbers into the second box at the top of the initial search box.
R00003264 will take you to the Annual Report of the D of M for 1900. Notes on diamond mining for that year are on pages 60/61 of the report.
R00050830 takes you to the document “Industry 18: Mineral Industry NSW - 1980 - Gemstones 2nd Edition”. The section dealing with diamonds is on pages 32/67.
R00047949 brings up the most comprehensive document of them all – “Diamonds in NSW”, from which much of the previous document has been taken.
So you want to go and look for diamonds yourself? The references above will give you lots of clues to locations, nearly all of which will turn out to be privately owned. Make sure you get permission before entering any private property and respect the wishes of all landowners.
Staggy Creek on the Copeton Dam road near Inverell is the only place that seems to be easily accessible to the public. Google Staggy Creek fossicking and you will find lots of web pages to explore. Some of them even mention finding diamonds there! Check out my entry in myBlog as well. You can always go and look at the specimens at the Inverell Tourist Information Centre if you want to compare your finds with the real thing.
The illustrations accompanying this blog were adapted from the above references and similar ones found on DIGS.

I also recommend you check out my video on the subject, which does not include any footage of actual fossicking but does reproduce these illustrations and other similar ones. The link is here.

Addition 27/06/2015. I came across this interesting ebook today. It's called Sydney and the Cudgegong Diamond Fields, written in 1870 by Angus Mackay, MLA. It describes a journey from Melbourne to Sydney by ship, then by train to Bowenfels (the end of the line in 1870) and on via Mudgee to the Cudgegong River, where diamonds had been discovered not long before. It really does give a great insight into the conditions of the times. Download from Trove here.