Search This Blog

Wednesday, 11 October 2017

THE GRAFTON-MACLEAN METALLOGENIC MAP




The NSW Geological Survey has compiled an extensive series of reports which can be used to assist in the search for new mineral deposits or simply to locate existing ones. The Grafton-Maclean Metallogenic Map group of documents may be downloaded from DIGS (here) using this reference number: R00056102. The files take up about 65 MB and consist of many related documents apart from the map itself. These represent the original report broken up into sections.
The map includes the Torrington and Emmaville districts and extends southwards to Glencoe. The western edge of the sheet joins the Inverell map, and it extends to the coast in the east. The Inverell map will be the subject of a later blog.
The map provides a vast amount of information – geology, structure and mineral deposits as well as the underlying topography, roads, watercourses etc. This can make locating something quite difficult and frustrating, so it’s important to become familiar with the meaning of the colours and symbols provided around the margins of the map. Here is an example of what the map contains:

The rest of the documents in the downloaded folder provide information on the background geology and the individual mineral deposits. Take, for example the deposit number 1837, roughly in the centre of the extract. The table of mineral deposits (left of map) describes this as “Back Plain Creek sapphire (Zr)”.
You will find the deposit listed in the file titled “Text_4.3MB_zip_of_4_deposit;_pdf” (the first of four of these). When the file is open, scan through until you come to “GR 1837”, which is the extract below.
More information can be found by looking up the Mineral Occurrence List in the second part of the above file, using the same deposit number (1837).
 You could expand your knowledge of the area by searching other deposit numbers nearby, whether you can find them on the map or not.
Another possibilty is to search the Mindat data base (here) using the mine name. This is what you will find for Back Plain Creek:
Located approximately 15kms NNW of Glen Innes.
Operated as a small open cut and shallow pits 1971 to 1990s.

Mineral List



2 entries listed. 1 valid mineral.

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

References

Metallogenic Study and Mineral Deposit Data Sheets: Grafton-Maclean Metallogenic Map (SH/56-6, SH/56-7), Geological Survey of New South Wales, 2001: HF Henley, RE Brown, JW Brownlow, RG Barnes and WJ Stroud. Published by the Geological Survey of New South Wales.

Finally, you might like to check out my blog on the Back Plain Creek area here.
Here is a link to a slide show of pictures from the data package: here.

Sunday, 5 February 2017

STAGGY CREEK GEM FOSSICKING AREA NEAR INVERELL NSW AUSTRALIA


Extract from "Diamonds in NSW"
Staggy Creek reserve is one of the few places in NSW where fossickers can go and have at least some chance of finding an alluvial diamond. It’s part of an extensive deep lead lying beneath the basalt, south of Inverell. Tin (cassiterite) was the main mineral being sought by miners in this area in the nineteenth century and diamonds were discovered during the search. This created a lot of interest at the time – and still does, judging by the amount of prospecting that has been going on during the last twenty years. Search DIGS (here) using “Staggy Creek” as the locality and you will be surprised.
There’s a lot of good background information in my Blog “Alluvial Diamond Mining in the New England Region of NSW Australia” (here) and especially in the NSW Geological Survey publication “Diamonds in New South Wales”. You can download a copy from DIGS; the reference number is R00047949.
I’ve been there just once, at least 25 years ago. All I can remember finding is pieces of black tourmaline, which are everywhere.
Here’s what the Inverell Tourism website (here) has to say about Staggy Creek:
Copeton diamonds - Australian Museum
The district’s rich volcanic soils can offer other gems and minerals. One such gem, is the amazing Diamond found near Copeton Dam; the Staggy Creek Fossicking Area provides a site where you can look for the Diamonds together with Black Tourmaline and Quartz. This is a rough dry area 28km from Inverell, you can take your water or dry sieve.
Contact Details: Copeton Dam Road (24km from the turn off Copeton Dam from Inverell)”      
This is what “Diamonds in NSW” has to say about the place.
Photo courtesy of Jewellery Pirate
The Staggy Creek deposit is an isolated area of diamond-bearing Tertiary gravels exposed at the surface. There is no basalt overlying the deposit and granite bedrock surrounds the Tertiary gravels. The granite is remarkable in that it contains a number of potholes of circular shape and its surface appears to be the surface on which the Tertiary sediments were deposited.
The deposit consists of quartz pebbles, cobbles and boulders ranging from 5mm to 0.2m in diameter, jasper, a relatively large amount of tourmaline (much of which is unabraded), topaz and garnet (which is invariably present in the diamond bearing gravels). Many of the quartz boulders contains pencil tourmaline. An ironstone band similar to those at Kirk’s Hill and the Banca is present.” Read page 52 of the report for a fuller description.
Mindat (here) includes a reference to Staggy Creek.
Photo courtesy of Jewellery Pirate
Staggy Creek lead, Copeton DamHardinge Co.New South WalesAustralia
Latitude & Longitude (WGS84):
29° 50' 5'' South , 150° 53' 5'' East
Latitude & Longitude (decimal):

Map sheets: SH 56-5, 9038-II-N. Coordinates: 295600mE, 6697500mN.
Placer deposit.
Rather strangely, the Mindat list doesn’t include ‘tourmaline’, the most obvious mineral at Staggy Creek.
Here is a list of other resources you will find interesting.
Photo courtesy of Jewellery Pirate
Jewellery Pirate’ Blog (here). Thank you, JP, for the photographs of Staggy Creek.
An account of a visit by the Campelltown Lapidary Club (here).
Paul Clacher’s visit (here).
All Travels website (here).
World of Shiny Stuff website (here).

Sunday, 1 January 2017

BLATHERARM CREEK TORRINGTON TOPAZ FOSSICKING




Blatherarm Creek (Blather Arm Creek, Blather Creek) is one of the most popular fossicking areas in the Torrington (NSW) district. This is partly due to the provision of a camping area there, but mainly because of the many topaz cutters which the creek gravel produces.

The map has been extracted from a publication of the NSW Geological Survey called “Rocks, Minerals and Landforms of the Mole Tableland which appeared in 2014. The DIGS reference number is R00059626. DIGS is a site from which a vast number of useful references can be downloaded. (here) I haven’t visited Blatherarm for more than 20 years so I have made use of some photographs from the Australian Lapidary Forum site (ALF here).  Thank you to those who contributed these to ALF.

The earliest reference to topaz at Blatherarm that I have found is in TWE David’s monograph on the
Vegetable Creek Tin-Mining Field (DIGS reference R00031676) page 70, where he writes “The sand and clay in these alluvial workings, in portion 42, parish of Bates, county of Clive, are from 10 to 15 feet deep, and consist of subangular granite sand, with subangular and rounded quartz pebbles up to 6 inches in diameter and rest on a bottom of granite. White topaz and sapphires are very abundant.”


Other Geological Survey references dealing with the area have this to say. “The Mole Granite area is also well known for topaz crystals ranging in colour from clear to straw yellow to blue and up to several centimetres in size. Topaz crystals or fragments can be found in all creeks draining the central Torrington pendant. The topaz originates from numerous silexite or quartztopaz bodies that mainly occur within the Torrington pendant or from the numerous narrow silexite dykes within the Mole Granite. Blather Arm Creek is particularly well known for its clear and blue topaz crystals and a significant amount of topaz has been found in Scrubby Gully and Highland Home Creeks.”


It was later found that the presence of rare corundum in local creeks was commonly known by local miners and fossickers. Other known localities are Blatherarm, Cattarrh, Bald Rock and Slow Gully Creeks. The source of the corundum is unknown but may be derived from the remnants of high level Tertiary gravels.”

I’ve mislaid my source for these quotes, but they are probably from Industry 18: Mineral Industry NSW - 1980 - Gemstones (2nd Edition) (DIGS reference R00050830), Exploration Data package Clive 1:100 000 sheet (DIGS reference R00031737).

Other documents you could consult include these:

Jewellery Pirate’s blog (here), a Mindat article (here) and the Minerama book (Topaz 1995) (here).

Beryl also turns up in the Blatherarm gravel. It is the typical pale green colour of Torrington beryl and is usually opaque. You cannot concentrate beryl in the sieve centre the way you can topaz because its specific gravity is nearly the same as that of quartz. You will need to look through the stones in the sieve to find any.

The source of the beryl is probably Bollinger’s Lode, which outcrops on private land upstream of the
Conservation Area boundary. Resist the temptation to trespass on this or other adjacent land. The best topaz fossicking is in the permitted area anyhow. Most of the land upstream appears to be swampy. When I was last there, I found most of my topaz by dry sieving old dumps away from the creek (top sieve only), collecting the sieve contents in a bucket and then resieving this material in the creek.
It is worth noting that radioactive minerals have been discovered at Bollinger’s and nearby locations. Torbernite is the most abundant of these. See Bollinger's Prospect, Torrington (DIGS reference R00039360)