Search This Blog

Saturday 20 December 2014

SAPPHIRE DEPOSITS NEAR THE GWYDIR HIGHWAY EAST OF GLEN INNES

Dirty Creek is in the centre of the map (from DIGS R00050764)
When I first moved to Glen Innes in 1988 I had with me a copy of the Records of the Geological Survey of NSW 14(1), which contains a valuable article titled “Sapphires in the New England District, New South Wales”. If you would like to download a copy, the DIGS reference is R00050764. The map at the end of the document is a useful tool for locating interesting fossicking spots. I need to point out, however, that, apart from Yarrow Creek, some of our best sites (eg Pretty Valley, Rainy Swamp, Back Creek and Frenchies Swamp Creek) are not indicated as sapphire bearing at all. The map in Mineral Industry 18 Gemstones 2nd Edition (1980) DIGS reference R00050830, is based on the earlier one.
Dirty Creek 1652 Tarcoodie 1704 (from metallogenic map)
One place seemed to be remote from all the others and that is Dirty Creek, near the Glen Elgin road turnoff from the Gwydir Highway about 30km east of Glen Innes. See the map extracts for guidance, also Google Earth. I now know that there are gemstones to be found in many creeks in the Glen Elgin area but it isn’t an area I’ve looked at very closely. Dirty Creek is crossed by the Glen Elgin road immediately after the turnoff from the highway. After a few hundred metres, the creek joins the Rocky River almost at the highway bridge. The Rocky River is known as the Timbarra River further downstream.
Please note that anything I say about access may no longer be true. Under no circumstances should you enter private land without permission.
Stock reserve gate
There is some kind of stock reserve covering the lower parts of Dirty Creek. About 300 or so metres before the turnoff there is a gate opening into the reserve on the northern side of the highway. The creek runs through swampy and sandy country and you wouldn’t expect to find much in it. All I ever turned up were a few very waterworn sapphire and zircon fragments as well as black spinel and tourmaline. These were more abundant downstream where there are granite outcrops. Upstream you come to the boundary fence. Note that the area shown on the Grafton-Maclean metallogenic map as being the site of mining activity is a km or so upstream. Dirty Creek is shown as deposit number 1652
I haven’t examined Dirty Creek between the Glen Elgin bridge and the junction with Rocky River, but there are many granite outcrops in this stretch so there could be some gemstone concentrations waiting there for those who don’t mind getting wet.
Rocky River reserve entrance
Immediately after the highway bridge there is a track on the northern side entering what appears to be another reserve, through which the river flows. A lot of fossicking has been done here because there is usually a good flow of water and there is a lot of gravel in the river and its banks. I’ve only washed a casual sieve or two, but they always contained some gem material. It’s my guess that this has come down Dirty Creek and into the Rocky as I could find nothing upstream of the Rocky River bridge, though the usual problems of swampy ground and access to the river make this statement difficult to confirm.
The third gem bearing spot in the area is Tarcoodie, which I have not been able to locate, though the mine data information suggests that quite a bit work was done on the deposit. It is shown as deposit number 1704 and ought to be on the southern side of the road in the vicinity of the prison farm (afforestation camp). Stay out of that area!

Extracts from Grafton-Maclean Metallogenic Data

GR1652 (YJ0011) G Dirty Creek OCC sapphire modern placer (fluvial)
NAME(S): Dirty Creek Recorder(s): K. Ringwood, 24/11/1995
LOCATION Map sheets: SH/56-6, 9338-IV-S Coordinates (MGAz56): 404206mE, 6721488mN Locality: 29 km ENE of Glen Innes
Location method: 25K topo map Co: Clive Ph: Lewis Por: 42, 43, 45
MINING HISTORY Workings: dredging or sluicing Extent (m): d: l: 2000 w:
Prods and period:
Exploration:
HOST ROCK(S): clastic sediment, alluvium, Quaternary
DEPOSIT CHARACTER Ore minerals: (sapphire) Alteration:
Gangue: Production: Resources:
Ore genesis: modern placer (fluvial) Relation to host: stratiform Orientation:
REMARKS:
REFERENCES: MacNevin (1972), MacNevin & Holmes (1980)
GR1704 (YJ0010) G Tarcoodie deposit OCC sapphire modern placer (fluvial)
NAME(S): Tarcoodie deposit Recorder(s): H F Henley, 7/2/1992 & 24/11/1995
LOCATION Map sheets: SH/56-6, 9338-IV-S Coordinates (MGAz56): 409405mE, 6720368mN Locality: 36 km E of Glen Innes
Location method: 25K topo map Co: Clive Ph: Mount Mitchell Por: 21, 22; PMA
MINING HISTORY Workings: dredging or sluicing Extent (m): d: l: w:
Prods and period: Gem Exploration (July 1971 - March 1972)
Exploration: G and J Gems P/L (1988-present)
HOST ROCK(S): felsic intrusive, granite, Quaternary sediments, alluvial plain, Quaternary
DEPOSIT CHARACTER Ore minerals: (sapphire) Alteration:
Gangue: Production: Resources:
Ore genesis: modern placer (fluvial) Relation to host: stratiform Orientation:
REMARKS: substantial conventional production plant type
REFERENCES: GS1990/226

My gem hunting/mining You Tube playlist may be found here. I have 3 other playlists - 

the Blue Mountains, Glen Innes and New Zealand.


All New England and other Geology blogs and videos

Thursday 11 December 2014

THE EMERALD MINE NEAR EMMAVILLE

The Emerald Mine (before 1900)
Any book produced for “rockhounds” in Australia (from the 1950’s on) will mention The Emerald Mine, such is the fascination of this beautiful gem.
I have several in front of me as I write. The first is The Australian Gemhunter’s Guide by KJ Buchester (1965). Writing of Australian emerald deposits, he says “The New South Wales deposit was the first to be discovered, in 1890, at a site about 6 miles north-north-east of Emmaville, a small town 24 miles north-east of Inverell. This location, known as de Milhou’s Reef, had originally been mined for tin, and emeralds were later observed in the old mine dump.
Thereupon a company was formed to follow up the emerald bearing veins.” Buchester then gives some production figures and recounts some of the problems encountered by the miners. He also mentions a specimen in the Australian Museum, no doubt one of those which excited me when I was a teenager.
Later in the book he mentions that the mine was probably under lease and that emerald, beryl, topaz, quartz crystal and fluorspar could be found there.
The second book is “Australian and New Zealand Gemstones”, edited by Bill Myatt (1972). He writes “Near Emmaville in northern New South Wales active mining was carried out in the latter half of the last century. The gem was extracted from a pegmatite dyke and occurred in association with cassiterite and topaz.”
Now all this information is true, but if you are longing to get at those dumps, take note of the fact that most of this material has since been pushed back into the old shafts and access to the public is strictly prohibited. It may be possible to go there with an organised group during Emmaville’s biannual Gemfest, but even that is unlikely. If you want more specialised information on the locality, get hold of a copy of the 1993 Minerama book, “Beryl” from the Aussie Sapphire website (here) (not available). If you aren’t a member of the Australian Lapidary Forum (ALF), this would be a good time to explore the site (here).
The photographs on the right were taken in July 1993 as we were preparing field trips for Minerama that year.
Diagrams from David's report
DA Porter on his rounds
TWE David, in the process of becoming Australia’s best-known geologist at the time, reported on the finding of emeralds near Emmaville in the Annual Report of the NSW Department of Mines for 1891 (DIGS Reference R0001418). The report is found from pages 229-234 and is very thorough, in typical TWED style. The  Sydney Morning Herald commented on David’s findings (here). In almost any reference you consult, Mr DA Porter of Tamworth is given credit for the discovery of emeralds at de Milhou’s Reef. He himself downplayed his part in a letter to the Editor of the Herald 2 days later (here), naming Mr AB Butler of Port Macquarie as the true discoverer. History has not been as kind to Butler as it has to Porter and I haven’t found out anything else about him (yet). Donald Alexander Porter was an inspector of school buildings in northern NSW and travelled extensively through the very active mining regions of his day. He not only collected many fine mineral specimens but also had a number of papers published in the Journal of the Royal Society of NSW. A lot of the specimens he collected are now in the collection of the Australian Museum in Sydney, perhaps including the one illustrated. My thanks to the publishers of the Australian Journal of Mineralogy, Volume 4 No. 2 for some of this information and the photographs of Porter and the museum specimen.

There is a lot of information freely available about this particular mine and you can use the resources given in the Blog entry on Reid’s Copper Mine as a guide. An important source of information is the report by Wynn and Loudon (1966) titled “The Emerald and Associated Mines”. The DIGS reference is R0005608. Unfortunately, my copy has been missing for years, suspected of being retained by one of my Moss Vale High School students. The copy you will download from DIGS is missing the maps and sections, showing what a popular location the Emerald Mine has been! Fortunately, I have a copy of these in PDF format and the illustrations at the end of the Blog come from this. I hope you can read it. You can enlarge them.
If you are in Emmaville, make a point of visiting the Mining Museum (here) (doesn't work). As well as specimens from this particular mine, there are many other fine minerals to be seen. See also this article from Geohavens (here)(doesn't work) for further information on Australian emeralds. 
You will find my You Tube playlist on gemstones and mining here. I have three other playlists - on the Blue Mountains, Glen Innes and New Zealand.

All New England and other Geology blogs and videos
The missing illustrations from Wynn and Loudon's report


Tuesday 25 November 2014

REID’S COPPER MINE, NEAR EMMAVILLE NSW AUSTRALIA

My attention was first drawn to a place of this name when I was looking over the Grafton 1:250000 geological map. I can’t locate a download site for this map, but you can get the 2001 Metallogenic map here. I was primarily interested in locating Webb’s Silver Mine (see my Blog on that place). Right on the road from Emmaville is the number 12, which the legend tells me is the location of Reid’s Copper Mine. On the 2001 map the number is 1053.
I made the trip out there on the 10th October, 1988. The spot is on the left hand side of the road, shortly after a steep climb. This is the Grampians ridge and there are good views back towards Emmaville and ahead to the Mole Tableland. The location (at
that time, anyway) is entirely in the road reserve. I observed two shafts, nearly filled in with rock rubble and general rubbish. A narrow mineral vein was present in the wall of one of the shafts and the rock appeared to be quartzite. There was some quartz feldspar porphyry on the dumps. I collected specimens of malachite, azurite, a sulfide mineral (which was most likely chalcopyrite or pyrite) and fluorite from the dump. There was clear, pale green and occasionally purple fluorite scattered all over the dump, especially on the side away from the road.

Subsequently, I described the location as a possible self-guided field trip in the first Minerama book (Molybdenite) which may be downloaded here (doesn't work) via my Blog from the Australian Lapidary Forum (ALF) site. This made the place well known to fossickers, so whether or not you can still collect similar material today I can’t say. If someone has been there recently, then making a comment (below) letting us all know what the place is like now, would be most welcome.

Here is the earliest report I have been able to find. It’s from Edgeworth David’s report of 1887 “Geology of the Vegetable Creek Tin-Mining Field”, page 160. You can download the entire document from DIGS: Reference number R00031676. Note that there is no mention of fluorite.
This extract is from the report titled “Grafton Maclean 1:250 000 Metallogenic Map - Metallogenic Study and Mineral Deposit Data Sheets (metallogenic explanatory notes)” downloadable from DIGS (here). The reference number is R00056102. The map referred to in paragraph 1 is included in the download.
When you read this, it is obviously referring to the same place I visited in October 1988. Again, it is curious that there is no mention of fluorite. There are several possible explanations. One is that I mistakenly identified some other mineral as fluorite, perhaps quartz. This is unlikely, because I’ve been there with others several times since and we have always found fluorite on the dump. Another is that when the geological field work was done for the metallogenic study, the location was confirmed but the information on the minerals was taken from David’s 1887 report. If this in fact some other prospect and not actually Reid's Copper Mine, then we have a possible solution to the dilemma.

JE Carne’s report “The Copper Mining Industry and the Distribution of Copper Ores in New South Wales” (1908) (DIGS reference R00050669 ) gives information about numerous copper mines and prospects. The New England section begins on page 304. Scanning through this “mine of information” shows that, in the Emmaville district, copper minerals and fluorite had been found together at the Bald Nob Mine, about 5 miles north of Emmaville, and Portion 2, parish Paradise North, County Gough. So there is certainly a precedent locally for this type of occurrence. Perhaps there has been some confusion between locations at some point.

Another useful reference on the Net is Mindat (here). This is a remarkable world-wide data base on almost anything to do with minerals. Searching for “Reid’s Copper Mine” only gives information we’ve already quoted above; there is no mention of fluorite. David places it in "Portion 600, Parish of Strathbogie North". Mindat says "Portion 61". 

Bald Nob Mine” confirms the occurrence of fluorite and copper minerals. The location of the mine is said to be approximately 2km north-east of Emmaville. Searching for “fluorite” and “Emmaville” simultaneously brings up quite a few fluorite localities, amongst which is “Reids/Willowie Mine”, approximately 3km north-east of Emmaville. Then there is “Say’s Prospect”, approximately 6km WNW of Emmaville, Wells’ Lode 1, approximately 6km north-west and Well’s Lode 3, approximately 7.5 km north-west.
All this suggests that there must be more mine dumps in the area worth locating. Add a comment below if you would like to share further information.
My You Tube playlist on gemstones and mining is here. I have three other playlists - the Blue Mountains, Glen Innes and New Zealand.

All New England and other Geology blogs and videos

Friday 14 November 2014

WEBB’S CONSOLS AND RELATED MINES, STRATHBOGIE NEAR EMMAVILLE

Mine cluster south of Strathbogie
A group of sulfide ore bodies has been mined or prospected about 15 km south west of Emmaville. I have not visited any of these places; I assume that they are all on private property and under mining leases or covered by exploration licences. If any reader can provide information about accessing these locations, please advise us in the comments area at the end of this blog.
Here is a list of prospects I have come up with – all appear to be in the same general area. Webb’s Consols, Wellingrove Silver Mine, Mt Galena, Matthews Mine, Seaton’s Mine, Munsies Prospect, Lucky Lucy, Castlereagh, Barton’s Quarry and Tangoa. In every case, there appears to be an association with the Webb’s Consols Leucogranite, most often by way of quartz rich veins and pipe-like structures. Some of the ore bodies have actually formed in the Permian volcanic rocks which the leucogranite has intruded. The map from which the extract opposite is taken is included in the downloadable report "Inverell Metallogenic Map 1:250 000" (DIGS reference R00050906).
Minerals recorded include galena, sphalerite, arsenopyrite, chalcopyrite and pyrite. Silver is almost always present in the ore in significant percentages and its presence was the main reason for mining.
The Webb’s Consols mine has been the most productive to date, though one hundred years have passed since profitable mining took place there. At least 19 000 tonnes of ore were extracted (yielding 100 000 ounces of silver), most of this before 1901.
The earliest reference I have found is in the Annual Report of the Department of Mines for 1875, page 111. It reads as follows. “About 14 or 15 miles westward of Glen Innes, in the neighbourhood of Wellingrove, a lode was found which showed on the surface indications of copper, and when sunk upon to a depth of 14 feet a vein of pure galena was met with and worked, but carriage of the ore to the coast being too expensive to allow a profitable return, operations are at present in abeyance.”  This is well before the coming of the railway to Glen Innes, so the ore would have had to be sent to Grafton, a long and expensive process. No doubt the reference is to the Wellingrove Silver Mine.
Share Certificate from an early company
A problem common to all these mines was the difficulty experienced in separating the lead ore (galena) from the zinc (sphalerite). This was the same problem experienced at Broken Hill, where for many years the zinc concentrate was dumped, despite its containing valuable lead and silver. The flotation process, now normal practice in the industry, was unknown when these small mines were active, though to what extent it would have helped is unclear, considering the relatively small quantities of ore available.
Some of these old mines, especially Webb’s Consols, are currently under investigation by Silver Mines Ltd, though the present (November 2014) price of silver is not exactly encouraging.
There are numerous references from which you may gather information, starting with a presentation to Shareholders by Silver Mines Ltd. (here) (missing). An interesting newspaper report from 1891 may be found here. There are many references in old Geological Survey reports. Go to DIGS (here) (evidentally changed) and put in “Webb’s Consols” for location and you will find lots of information. One of the best of these is called “Webb's Consols - Wellingrove and Mount Galena Mines. Extracts of Annual Reports from 1875 to 1954”. The DIGS reference number is R00025719.
Another well-presented report is to be found in EF Pittman’s “The Mineral Resources of New South Wales”, 1901.  The DIGS reference number is R0005137. The section dealing with this group of mines begins on page 112. The photograph of the mine is also found in this book.
My You Tube playlist on gemstones and mining may be found here. I have three other playlists - on the Blue Mountains, Glen Innes and New Zealand.
From the "Horse and Buggy" days, minus the horse

Sunday 28 September 2014

THE OTTERY MINE, TENT HILL NEAR EMMAVILLE NSW AUSTRALIA

The site in December 1967
The Ottery Mine is one of the few places in NSW where the public can go and get a good idea of what went on at a mine in “the good old days”. Usually, such sites are out of bounds, being on current mining leases or private land or considered too dangerous to allow people in. The Ottery is different – a lot of money has been spent to make the old mine site accessible and provide good information so you can see for yourself how it all came together.
The mine is close to the Tent Hill-Torrington road just a few km from the old tin mining town of Emmaville, itself about 40km from Glen Innes. For more information on how to get there and what there is to see, I recommend the following websites: Aussietowns – Emmaville (here), the Northern NSW site (here) and Aussie Sapphire’s Blog (here).
The site in May 1991
Before I move on to more technical stuff, here are few personal observations which might enhance your visit.


I first saw this place in December 1967. The main features haven’t changed greatly since then – the chimney, the condensing chambers, the damaged environment (though this has been improved a lot by the mine site rehabilitation that has gone on since then.) In 1988 I collected specimens of pyrite and arsenopyrite there. You can still smell the sulphurous odour around the site. I observed (on the right near the car park) that there were a number of decaying wooden barrels which still contained a whitish substance. Maybe they are still there and perhaps it is refined arsenic oxide (as I first thought). More likely it is cement, which was delivered in barrels before the double paper bags of more recent years.
May 1991
On several occasions since then, I have been underground in the old workings (a potentially very dangerous thing to do), though most openings were blocked off even then. It was a real eye opener to catch a glimpse of the conditions in which the old time miners worked and to see the mineral veins in their natural condition in places in the rock walls.
As you will soon discover when you start reading about the Ottery, there were two main stages in the history of the mine. The tin stage began during the mining boom at Vegetable Creek (now called Emmaville) which commenced in 1872. Prospectors scoured the district, one of whom (Alexander Ottery) discovered the outcrop of the cassiterite-bearing veins sometime between 1875 and 1881. The mine was opened up in 1882 and the Glen Smelting Works was established to extract metallic tin. The site of the smelters is at the junction of the Emmaville-Deepwater and Torrington roads (Tent Hill).
From The Mineral Industry of NSW (EF Pittman 1901)
Eventually mining tin became unprofitable and the site passed into the hands of the firm William Cooper and Nephews (Australia), who then mined the arsenopyrite ore bodies to produce arsenic oxide which was widely used in the manufacture of sheep dip (1920’s on). This is the time when the surviving condensation chambers and chimney were constructed. There has been a lot of investigation of the site in more recent times and on several occasions when passing by on the way to Torrington I’ve observed drilling in progress on the hill. No doubt the price of tin is the key to any future mining there.
From The Tin-Mining Industry in NSW (JE Carne1911)
You could never call the geology of a site like this “simple”, but basically there are at least 5 quartz veins associated with fissures in a body of granite which intrudes claystone and tuff. This granite is probably related to the Mole granite to the north around Torrington. Arsenopyrite (FeAsS) and cassiterite (SnO₂) were the main ore minerals extracted, but pyrrhotite (Fes) and pyrite (FeS₂) are also present. As is common with such ore bodies, many other minerals have been identified in the ore, but are unlikely to be found as hand specimens.
To gain a better understanding of this place, and to see how it fitted in to the wider mining field, there are many good references you can download. Here are just a few.
A compendium of documents assembled by the Geological Survey of NSW may be found in DIGS (reference number R00045777). Doing a search in DIGS using the location “Tent Hill” and keyword “Ottery” will turn up much more. Of particular interest in the compendium is a document written by Harry Julius, whose father was the mine manager in the arsenic mining days.
The Minerama book title Cassiterite (1984) may be downloaded from here (doesn't work). See the part dealing with Emmaville in particular.
The Tin-Mining Industry in NSW 1911 by JE Carne (DIGS reference R00050677) was written near the end of the tin mining stage and has a good section on the Ottery Mine.
My You Tube gemstone playlist may be found here. I have three other playlists - the Blue Mountains, Glen Innes and New Zealand.

All New England and other Geology blogs and videos
The Ottery Mine in 1922. From Grafton/Maclean mine data information