Friday, June 21, 2013

Regolith Geochemistry

I just got back from a field trip with W. A. School of Mines which was a blast all round.

I caught up with me 'ole mate Kim and, turns out, the rumours concerning underground workers making sexist jokes at the expense of our beloved PM were utterly without foundation. Boy Oh Boy ! Imagine my relief !

Intriguingly, Dr Bob Fagan, our Geochem tutor, showed us a new(ish) technique of gold prospecting. It uses minimal equipment but can go well up the investigative pathway when you are considering regolith hosted nuggety gold in places like the Eastern Goldfields of Western Australia.

The old timers with the dollies, pans and ponies would have been looking for the classic Clondike placer "downstream from the motherlode" and this strategy would have lead them directly away from the paydirt.

My attitude towards prospecting is the same as fishing. I don’t like fishing but I do like catching fish. This is a key concept. Gram nuggets are scarcely worth bending over for.

The nub of what Bob was on about - Gold Prospecting Information to Help You Find Gold

I work for a company that builds EM Geophysical instrumentation for ground regional survey work. I am fascinated to know what sort of geophysical techniques are built into these top end recreational metal detectors. I have just finished my Post Grad. Diploma in Exploration Geoscience and since my background is in Electronics I am mostly interested in the Geophysics side of the field.

Gold just gets more interesting the more you learn about it. It requires a comparatively low concentration ratio to take it from background to minable. About 300. 

If it were an order of magnitude higher in background, we would see auricrete as well as the usual calcrete, ferricrete, silcrete outcrops scattered round the scrub and think nothing of them.

The value placed on gold with respect to it's actual utility is just another one of those utterly insane things we humans do.  The process of finding gold, using more smarts than sweat, is one thing, but a whole other vista exists in the Tenement game. "Two Up" makes far more sense.

You can almost imagine the element chuckling away to itself at us dumb humans playing all manner of permutations of the Long Con on each other, since the times of the Pharaohs.

The truly wondrous thing about gold is that a process that spans our lifetimes deposits the merest whiff of it in the ground. You gotta stick around.

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