Some observations on VMS deposits. VMS = volcanic massive...

Some observations on VMS deposits.
VMS = volcanic massive sulphide
They are often zoned into 3 ore types. Peripheral Ag - Ba, then closer to the source Pb-Zn-Ag +/-Au, and a feeder zone of Cu + Au.
East Australian examples tend to have elevated gold at 1 to 4g/t. They tend to have complicated metallurgy. Eg. Woodlawn recoveries were around 75-80% hence the large amount of metal left in the tailings dam that HRR are attempting to recover. The complicated metallurgy is often offset by high grade but sometimes sends VMS mines broke.
The silver resource represents the edge of a large system. The barium content appears to be to difficult to recover and is not considered in the economics. It would be a good question to ask if there is any potential to recover Ba?
The trick is to find the Pb, Zn, Cu cores at depth in 2 to 4 cubic km of rock. Kempfield has been tilted up on its edge. Work to date indicates that the core is still in the ground below the silver resource and not already eroded away.
An observation about silver is that a lot of world production (60%?) is by-product from other metals (mostly VMS and gold) that is fixed and produced independently of the silver price. The $A16.60 figure mentioned above is similar to projections at the time by Macmin and Cobar Consolidated for their respective deposits that proved to be fatally wrong with both companies going into liquidation.
I do think they have a good chance of finding an equivalent to Woodlawn and have good technical people.
PS
Woodlawn is 120km to the south of Kempfield in the same general group of rocks. The mine worked from 1978 to 1998 and had a premining resource of ~20Mt.