Ann: Bryah Basin Exploration Update, page-41

There was a paper in 2017 by Occhipinti, Shepherd and a few others, which moved on a bit further from the Hawke et al. paper. Shepherd et al. resolved some of the basin stratigraphy between the Yerrida and Byrah-Padbury basins, putting them back into what used to be known as the Glengarry.

The significance is that, effectively, the Ravelstone and Thaduna formations are basically identical, and overly the Narracoota. The contact is the setting of Horseshoe Lights, Wodger-Forrest-Big Billy, and BYH's Windalah (plus Fortnum, if you ascribe VMS characteristics to certain deposits there). 

The Karalundi Fm is the equivalent of the Johnson Cairn/Mooloogool and lower formations, including the Juderina and the Peak Hill Schist / Wilthorpe Fm. 

THe Narracoota Fm, as per Hawke and Occhipinti et al et al., plus old mate Pirajno and his Wotsname Member, interfingers with the lower formations. So work subsequent to Hawke et al, is showing that what previously was considered too old (Karalundi) is actually prospective. 

Also, the key idea is that it's not all layercakes; while the Narracoota was active in the east of the basin, sediment was still being deposited in the west, and then the magmatism moved west and south, bringing prospectivity into a different set of rocks. 

My concern, aside from not retrospectively ascribing knowledge-a-forethought to SFR's discovery of DeGrussa and using that erroneously to consider that they know the best and have always done so (which is illogical), is that the 'magic horizon' or 'corridor of riches' in the Narracoota/Johnson Cairn/Karalundi interval OR in the Ravelstone/Narracoota interval, shows a huge concentration of alteration centres, with stuff all actual VHMSs. 

Even accounting for the fact that mineralisation is not always economic, and counting the sub-economic strikes, we begin seeing a pattern emerging that barren, but sulphidic, alteration centres are vastly more common than mineralised alteration centres. 

Well Mineralised: DeGrussa, Monty, Horseshoe Lights

Mineralised: Forrest, Wodger, Big Billy, Citra

Barren: Cashmans, Orient, the stuff AUR sank the 850m diamond hole on, Vulcan, Callies-Yarlarweelor, Windalah (for Cu), Jupiter, Mars, and any number of conductors with jasperoid + sulphide + chlorite alteration + Ag-Sb-Mo-Te-blah blah 'signature'. How many have TLM, ENT, AUR, ALY, BYH, HOR, etc etc and SFR drilled that met these criteria? At least a dozen more.  

I mean...we know this all now, 10 years after the fact. So how did SFR know (that paper was in 2010, mind you, when Simich was still gasbagging about their multi-elements they ran after the discovery what told them retrospectively what was the sweet spot) that in 2008-09 they were on to a VMS? They didn't. 

DO they know how to separate crap alteration from good alteration? Possibly, which is why you would poach Dr Hawke, who theoretically should know the magic recipe. But the evidence (successful strikes) says that it either doesn't matter, in that there's no way to tell a Cashmans from a HSL, or they don't actually know, and will continue drilling barren alteration - which is quite ubiquitous - until they strike it lucky again.