is od vulcans child?

Hi Guys,

Like V8 I too think VUD15 will be looked back on as the discovery hole. I like this hole as it is the first hole with sufficient sulphides in OD like breccias to host 1% plus copper grades. Secondly the remobilized obviously cupriferous sulphides on the margin of the mafic dyke look very local compared to those in VUD3 which may be more distal.

It is interesting to look at BHP's published report "Geometallurgy at Olympic Dam" dated 2nd December 2011 in the context of Vulcan. I personally think Vulcan and OD are contemporaneous and that Vulcan is not something like OD, it is the same hydrothermal event but a different conduit. Therefore they should be very similar in geological signature.

OD is very iron and oxygen rich and sulphur poor for a hydrothermal event and this is probably why it is economic. Iron has been locked up by the excess oxygen leaving what sulphur there is for the copper.

Looking at sulphide mineral distribution at 400, 550 & 700 metres in OD a few things stand out.

a. There is relatively little pyrite in the system. If you find any quantity of sulphides you find ore.

b. Bornite distribution and high grade ore appear to be fairly tight on what was probably the prime hydrothermal conduits at the time copper, gold and uranium were precipitated on the declining pressure/temperature gradient as solutions approached the paleo-surface.

c. Chalcopyrite and pyrite are more peripheral and have funneled shaped distribution.

Why should Vulcan be different?

It is interesting to rescale images of OD, Carrapateena and Prominent hill to the same as Vulcan gravity/drilling plan and overlay them. The Vulcan Hydrothermal System is clearly larger in aerial extent than OD, much larger than Carrapateena and PH or DeGrussa would fit in the cracks. It is also interesting slide the Vulcan plan over an rescaled image of OD's 400VD metre copper grades. In only a small portion of the positions would a hole coincide with a "discovery thick intersection of high grade ore”.

Vulcan is not necessarily a bigger system than OD. Perhaps it is higher level and subject to less paleo-erosion. Simplistically, Carrapateena, OD and Vulcan could all be similar funnel shaped events with varying degrees of erosion to the present unconformity.

The big issue is the 800-900 metres of cover. Exposed copper elephants are relatively easy to find. You look for a big green hill which people have been digging into for the last couple of thousand years. The only realistic thing to do is look for blind deposits on geological and geophysical data. The only recent significant success I am aware of in Oyu Tolgoi in Mongolia and Escondida in Chile. Oyu Tolgoi is a 35mt+ copper resource that Rio plans to open pit to 500 metres and underground mine to depths approaching 2000 metres. Escondida is a BHP/RIO joint venture in the Atacama Desert of Chile. This is a supergene deposit form by strong vertical leaching of low grade porphyry.

A quick look around the world at the major copper resources shows that most of the copper elephants such as El Teniente, Chuquicamata, Bingham, Grasberg, etc have or are very close to reaching open pit mining limits and are moving to underground mine relatively low grade ore at depths of up to 2000 metres.

Rio’s Bingham Canyon open pit in Utah is approx 4.5km across and 1.3km deep. Rio were in the process of removing their final open pit dirt and developing a portal in the bottom of the pit to access the Northern Rim Skarn containing 730Kt copper, 1 MOZ gold and 13 MOZ silver at 1500 to 2000m VD. A small 165mt rock slide has thrown a big spanner in the works. Have a look at images of Bingham Canyon Landslide and associated articles on the web. One would think this could have a bearing on Rio’s decision on Vulcan.

Copper is not an abundant metallic element in the earth’s crust such as aluminium, iron or nickel. I have no doubt that in the next 50 years or so it will be produced by remote mining technology in the deep root systems of large hydrothermal systems and at lower grades than are considered economic today. The polymetallic nature of these deposits is a bonus.

As others have said on this forum, Vulcan has absolutely huge potential. OD on Copper equivalent is considered the World’s second largest base metal deposit slightly behind Noril’sk. Vulcan’s hydrothermal signature as exposed at the unconformity is clearly larger than OD. Perhaps OD is an offshoot from Vulcan. How many major mining players would want to be in there with Rio if TAS starts intersecting the right stuff? For a small cap explorer the potential doesn’t get bigger.

On an academic front:

a. Where did all the gold come from in the Proterzoic Witwatersrand Sedimentary Basin? Perhaps it shed from a hinterland in Gondwanaland which is now Antarctica and to a lesser extent South Australia. Perhaps a swarm of IOCGU breccias pipes were the source?

b. I an interview looking back on his career with WMC and the discovery of OD, Roy Woodall was asked where the OD mineralization came from. He answered “where has this astonishing concentration of copper, gold, uranium, sulphur and iron come from? We don’t yet know the answer. It’s a great question for the next generation or two of earth scientists to worry about”. The OD discovery was a remarkable piece of exploration. Personally I think that the answer to the question is that it has to be an extraterrestrial impact and that OD will prove not to be unique.

In closing my ramblings I ask myself why VUD15 assays are taking so long. One possible answer is perhaps they are rerunning them to check they are correct.

I am a share holder and do have a vested interest,

All the best,

Tasidevil