I understand that the flotation process should remove essentially all of the PMs from what will then be truly waste tailings. So the present 30k tons will yield 3k tons with all the PMs, and 27k tons that can be discarded (buried out back).

If you look at the flow chart, the FEED is milled (step not shown) and fed through the Gravitational Separation. This yields the Concentrates from Mill that are then smelted, but this only gets out 15% of the PMs. The Tailings from Mill (that actually still contain 85% of the PMs, which is the 30k tons stored on site) are then run through the Flotation and Leach cycles to remove (hopefully) 85% or more of the remaining PMs. My point is that I don't see the need for the Gravitational Separation step once the Flotation and Leach cycles are installed. Why not just take the milled FEED and put it straight into the Flotation and Leach steps? Those steps will work just as well on 5 g/t gold (the starting waste ore average) as on 4 g/t gold (the waste ore after gravitational separation has removed 15%). It also removes the need to smelt the concentrate, since the gold is removed electrolytically.

I'm not sure what happens to the silver, there may still be a need to get that out some way if the leaching or electrolytic processes don't get out the mineralized silver. And the present smelting process doesn't get out all the silver anyway, so they store the slag from the smelt. At some point they will probably have to send the slag out to get the rest of the silver out unless they go to a more complicated process.