Good effort on the analysis. Couple of points - you may want to...

Good effort on the analysis. Couple of points - you may want to update your zinc TCs to $315 (vs $285) as that is the latest TCs for qualities like NCZ. Knocks off A$2.7M from the Rev & EBITDA for Dec.
I’d also question your concentrate proceeds reversal, since prices have dropped since the end of last Q the provisional prices of the previous Q may very well be above final prices in the current Q - offsetting some of the reversal.

Of course for future qtrs the EBITDA/Cashflow forecast is highly sensitive to the zinc price so if the zinc price is below the US$1.05/lb it will quickly drop. If the price rises above this then it will go the other way.
All in all very little room for error both operationally and price wise.

Also not sure if you have factored the replacement of the financial assurance bond @ 40% of EBITDA.