When you put a stockpile on your balance sheet as an asset there...

When you put a stockpile on your balance sheet as an asset there is a judgement about how much cost to allocate to it. Once that is done there is a secondary process where you must make sure that assets are not overvalued (will return the value assigned to them). This should happen monthly with a crack management team and not be done periodically like this. This write-down is saying that they weren't worth what cost were assigned to them, so have to be written down to the current estimate of how much costs will be recovered when processed.
This can come from assigning too much cost to them at the time of production (errors) meaning profits were overstated at the time and are now being corrected.
It can also arise from various grades of stockpiles where some low grades due to declines in gold prices becoming uneconomic requiring those low grade stockpiles to be written off. Again this should never have happened in the first place.
Given AUD gold prices have been pretty stable, it looks like errors in the past to me.
Not sure the CEO understands this since he didn't have a gold background when he joined. CFO has been fired and never should have been appointed as he didn't have the right experience.
Hopefully new incoming CFO knows his job and won't be allowing this to happen.
It's only a $74 million mistake!