A Case of “Let’s leave it alone for a while”, page-8

Hello mulac1,

Thank you for your question re interpretation of the strength of the Electromagnetic anomaly (61000 siemens at Desert Dragon) First let me say that I am not a geophysisit and the true interpretation of what is happening there should be left to the very competent geophysics team of Newexco. The quick answer to your question is No! Unless the downhole EM equipment has some very sophisticated instrumentation in recent development of tools to be able to discriminate between the various sulphides that cause the anomaly. I am not aware that there is such sophisticated equipment that has been developed of late.

You see, The sulphides that constitute the sulphide mineral suite in the ultramafic environments consist dominantly of Pyrrhotite, (an iron sulphide) Pentlandite ( a nickel sulphide and Chalcopyrite ( a copper sulphide) - These can be in disseminated form (salt and pepper style distribution or as blebs and pellets) in the hosting ultramafic rocks. During the deposition of the ultramafics pools and eddies form in the magma flowing tongues and accumulations or pools of the suphides form in pockets or along contacts with the hosting sediments which ultimately consolidate to form the massive deposits which principally comprise all three minerals described above, and in the perfect set up other highly sought after minerals such as Platinum group metals, cobalt and lesser sulphides also consolidate from the soup as accessory minerals.

Here is the rub however, Pyrrhotite yields the highest readings of all the sulphides in question sometimes by a factor of 4 or 5 or more. ( I don't propose to list a table of comparative EM signatures as there are many variables) Sometimes when drilled, such anomalies will turn out to be principally of pyrrhotite with no or very little economic metals. That however is rare and I am not suggesting that that could be the case at Desert Dragon. But, one must be aware that the economic mineral grade in a massive sulphide suite can be poor compared to the iron sulphides comprising the system. We have evidence of significant disseminated mineralisation in the system to suggest that some of these massive plums could contain an economic resource. One such plum may be the off hole body that yielded the 61000 siemens anomaly.Let us be optimistic on that.

Depending on thee crystallographic structure of Pyrrhotite, it can be minus magnetic properties. In such an instance, using magnetic techniques, in conjunction with EM techniques, it may be possible to quantify a proportion of other sulphides in relation to Pyrrhotite thereby helping in the interpretation prior to drilling. There may be other factors that could influence the results, particularly if the hosting sediments and the ultramafics have magnetic components, and invariably magnetic iron is always present in these environments. I'm sure the Newexco boys have considered that.

mulac1 I hope I have not confused the situation and as I say I am not a geophysicist and may be I know a little to be dangerous.

Hang in for the technical ride anyway, it will make for an interesting story.
Cheers,

helmenesh