Back in 1985-86 i was involved firsthand in the mineral...

Back in 1985-86 i was involved firsthand in the mineral processing of the deeps (fresh sulphides / un-oxidised) from both the Golden Spec mine and blocks of ore that came from the second mine around the 1940-50's known as Blue Spec mine. We identified via fire assay fresh complex ores that would not not leach effectively (due to dissemination of the gold particles) even with ground to 45um and so left on surface due to very complex metallurgy in the day.

The pilot plant we used was designed and build by Minproc Engineers and in its day was a forerunner to whats know as Pressure Leaching.
Basically we used the pilot plant to treat 3 types of ore. Oxide, Sulphide ores and the very complex refractory ores that were completely locked up. some refer to these ores a refractory or complex ores due to the nature of the mineralogy. Theses ores were not successfully treatable event when overground (10-15 um).

This is the ore type that needs to be solved for IMHO as its associated with very high grades across the open cut mines and deep underground mines.

Everything that has been done to date with the metallurgy has all been done before. They are only solving for the easy stuff atm... and every mine has come unstuck by miscalculating the risk of these blocks when they turn up. "Fire assay burns up everything" but nature cant treat economically at these rates of complexity today.

Hope this helps and looking for some success from the ongoing testwork they are working on atm - it aint easy or it would have been solved such a long time again but when its cracked (i have faith it will be in the next year or so) then - $$$

Hope this helps

RT