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Wednesday, 16 September 2015

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 (alternative 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) of which this one (here) is a good example.
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 can download a copy of the book here. 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 (which you can locate in DIGS (here))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.
My gem hunting/mining You Tube playlist is here. I have three other playlists - the Blue Mountains, Glen Innes and New Zealand.