Depreciation is just shown to support calculation of tax, it...

Actually let me correct some things I said in my first reply to you - I didn't take into account tax & royalties and my cost $430 USD was net of tin credits and included tax & royalties. It's actually $400 USD pure opex cost, before royalties, tax & tin credits. Tin credits look to be estimated at $55 USD, quite significant. 1200 tonnes of tin, $20k USD.

Either way, $102 mil AUD free cash flow seems a reasonable and conservative estimate.

Depreciation is just shown to support calculation of tax, it doesn't actually effect the free cashflow. You can see in 8horse's post cash flow is just EBITDA minus tax. Tax looks like it is calculated as (EBITDA - depreciation) x 30%.

137.5-34.6 = 102.9. Depreciation isn't included directly in the cash flow calculation.