RE:Begins with Strings of Open Pit Mines Hello TX,
thanks for all your constructive thinking.
I'm going to add some of my homework that it may compliment yours.
"depositied in multiple conglomerate layers with differing grades.
(assay those cores) for CONTINUITY".
I am very long and overweighted here so quite prejudiced. I will fill my last tranch as we go through the thin zone, in anticipation of the next release.
I was a fluvial geologist way back when so I'm further prejudiced.
From the beginning, I was sure if this was at all like the pictures of kilometers of detector pits, It was going to be cheap to mine. And profitable at an overall average of 2-3 grs./ton. I call it dozer work. :-)
I absorbed just enough in my rocks for jocks degree that I've been able to wade through article after article written about that witts. It is shocking to me that after over 100 years of mining that basin, there is still no real consensus about the various factors contributing to those giant gold deposits. That's geologists for you... And we can be certain that this will hold true in the pillbara basin as well.
At this stage I am confident to share that the one thing that Purdy's reward and Comet wells have in common with South Africa is the age of "deposition". During this time a lot of gold came from somewhere, got moved around, precipitated on, and then a Lot later metamorposed.
In the witts the richest layer called a reef, is the basal "carbon leader" that is a time marker layer.It is still being mined, many klicks underground, 1/2 meter thick, with many many ozs./ton It's a well sorted quartzitic, gravel clast conglomerate, in some samples evidenced by eolian wind deflation as well.
There are also two or three upper reefs, 100's of meters above. They averaged 7 or so grs./ton and presently uneconomic at 'just' a few klicks underground.
GH is dealing with basal time at this point, a very immature (subangular) basalt, high energy deposit, with much larger clast size. Several lenses well over a meter thick a piece. No carbon marker as of yet. but relatively rich as is the carbon leader horizon. Who knows, the 'upper conglomerates' may end up correlating with the upper conglomerate layers in the witts. All of this will become apparent way before any mining goes underground.
Meanwhile with these very shallow dips you could open pit a good kilometer out into the basin before you've even dug down 80 meters; once again a lot of cheap ore with bulldozers. :-)