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Jul 2006 - Study of Volcanoes

Study of volcanoes reaping orebody benefits

Just as the modelling techniques have advanced significantly in recent years such that most companies appear to use either datamine, vulcan or surpac to model their orebodies, with exploration identifying potential mineralisation using techniques such as 3d IP, Roly Hills’ 4 winds technology, Nick Archibald’s fracsis fractal graphics, and leapfrog, the study of volcanoes has also significantly evolved.

We (ERA) are increasingly encountering both exploration and producing gold companies bringing in geological experts (who are well-known in some companies but not in others, such as Greg Corbett, Jeff Hedenquist, Grace Cumming and Jocelyn McPhie) who specialise in volcanoes and epithermals to find the keys to their orebodies.

The knowledge and understanding of volcanoes has increased through many people accurately observing and reporting them which has resulted in a greater understanding of how orebodies have formed and consequently how they can either be discovered or their quality potentially enhanced.

Sitting inside the lip of a volcano does give you a different way of looking at them as seen in Figure 1 of the volcano Nyiragongo, DRC, in February 1975 like a big fire at night, and with the vent almost perfectly circular. Fortunately it didn’t erupt on that occasion – it did about 2 years later and has done so a number of times since – classic Hollywood volcano stuff of volcanic bombs and lava flowing down the sides of the volcano and on through streets of towns many km away etc.

Some companies try as many expert opinions as possible because most of the experts appear to have their own theoretical models that can be applied to most orebodies, until the most logical one has been found.

Kingsgate’s Chatree for example appears to best fit the model of submarine (or under the sea) formation, and we recently visited one of their exploration properties which had stockworks adjacent to fossilised coral and brachiopods, crinoids etc. Having formed under the sea results in different formations (imagine or see milk swirling from having been poured in coffee or tea).

We have mainly encountered such experts being used in gold (such as at Chatree, Mupane, Busolwa and Gold Ridge) and occasionally on porphyry coppers, and they do throw up alternate ways of looking at geology that can result in discoveries. Only last week (6 July) BMA Gold reported a new high grade intersection targeting a deeper area applying the theoretical knowledge of one of the experts.

Whether they can be used to shed light on other orebodies to enhance them remains to be seen, but different viewpoints are often required.

The old saying that “gold is where you find it and not where it is supposed to be” recently sprang to mind on our July 2006 visit to Avoca at Higginsville where we saw visible gold in ultramafic such that the core assayed ~10g/t for ~5m into the ultramafic hangingwall above the position of the quartz lode. The grade was in the lode too, but the ultramafic had always been regarded as barren – until now.

Perhaps your orebody can be re-interpreted and/or enhanced too ?

Disclosure and Disclaimer : This article has been written by Keith Goode, the Managing Director of Eagle Research Advisory Pty Ltd, (ERA, an independent research company) who is an Authorised Representative with Taylor Collison Ltd, and with his associates, may hold interests in some of the stocks mentioned in this article. The opinions expressed in this article should not be taken as investment advice, but are based on observations by the author. The author does not warrant the accuracy or completeness of any information and is not liable for any loss or damage suffered through any reliance on its contents.

Figure 1. The Vent of the Nyiragongo Volcano at night in February 1975GDNjul06

  • Written by: Keith Goode
  • Saturday, 01 July 2006

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