if the assay samples are confirmed A mediuum size gold deposit...

if the assay samples are confirmed A mediuum size gold deposit of say 50,000 to 300,000 oz Au may be a possible target !

Part 2

Madagascars potential

Madagascar offers plenty of scope for modern exploration. Its well exposed terrain is ideally suited to remote sensing, particularly because of the strong relationship between Madagascar's goldfields and tectonics (Madagascar is arguably the most fractured fragment of Gondwana).


The enormous advancement in modern soil and rock geochemistry have all but passed Madagascar by. So has the application of metallogenic models developed in the last 20 years in regions geologically similar to Madagascar - in some cases with outstanding success.

In spite of some minor French and Soviet involvement, Madagascar's gold resources have not really been assessed in recent times.

In exploration for primary gold deposits the concept of size is very important. South African gold mining companies, few in number, very large and bent on the necessity of replacing their increasingly uncompetitive mines, will probably be uninterested in a project with less than 1M oz of contained gold. A possible but a totally speculative type of deposit in underexplored Madagascar.



On the other hand the very successful and well diversified Australian gold sector operates more than 131 mines with an average production of around 60,000 oz/y. (Pollock, 1995). This a far more realistic target for Madagascar's presently known potential.

The exploration for medium-sized gold deposits (say 50.000 to 300.000 oz Au) seems to make particularly good sense in Madagascar: they are statistically more frequent, easier to finance and develop, gentler on the environment, more attuned to the decentralisation will of the Malagasy authorities and likely to produce less economic and regional distortion of Madagascar's fragile economy.

In any case, exploration for primary gold in Madagascar will demand commitment.

To reinterpret the incredible wealth of accurate, if obsolete, geological information will require time and
skill. The country has a proud history of self-sufficiency and gold is already its major mineral product.

Predictably, the Malagasy authorities (already bitten by some recent, hare-brained schemes regarding their gold resources) will require their potential investors to be serious. Given Madagascar's unquestionable geological potential this is only fair.





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Australian experience is relevant to Madagascar in many ways.

Many goldfields which were very productive at the beginning of the century came to an abrupt halt in the second decade of this century.

Classical example is Charter Tower gold field, the fifth largest in Australia where not an ounce of gold has been pulled out of the ground since 1917 and only recently being reinvestigated. In previous years 6.6 million oz was extracted from high-grade quartz veins which bear some similarities to most of Madagascar's goldfields.

At today's price this means well in excess of US$ 2 billion. Then the gold price fell 50% between 1910 and 1920, mining operations were small and inefficient, and labor became scarce and expensive because of other opportunities.



Some authors (Borg 1995; p 74) have given a good account on how modern exploration techniques can be applicable to gold exploration and evaluation situations in a variety of different anomalous environment. Several relatively inexpensive techniques such as soil, rock and gossan sampling, detailed exam of old working and known mineralisation have given good results in almost all cases and particularly for the associations gold-pyrite which is very common in Madagascar.



In considering gold ventures in Africa the objectives of the explorer are all important:

the five major South-African gold producers, bent in substituting what are now very deep and costly mines would not seriously consider a gold resource below 1 million oz gold (or about 30 kgs in situ resources).

So probably will be the view of some of the major Australian mining houses: BHP,CRA, WMC, etc. On the contrary for some small speculative company from Perth or Toronto the main consideration would be the "profitability" of the venture and much smaller resources can be considered provided the grades are there: this indeed has been the philosophy in Western Australian goldfields for the last 15 years.

Lastly some medium-sized companies consider their strategic medium term objective to become a plus 250.000 ounce gold producer through mining development in Africa (Cowley, 1995; p 146). At this stage of our knowledge Madagascar offers scope to all these objectives.



The metallic associations of many Madagascar's gold districts
would make the modern use of soil and rock geochemistry highly effective, much as it has happened in geologically contiguous Tanzania.

Two considerations are worth keeping in mind:



1) that for the forseeable future the geological risk on gold exploration in Madagascar is not going to be significantly decreased and



2) That medium sized gold deposits (say 50,000 - 500,000 oz Au) are statistically more frequent than very large ones (1,000,000 - plus oz Au) thus lessening the geological risk.