I guess the response of the company would be they hoped they could catch up the lost production but at some point it became clear that wouldn't be possible. Given the guidance was already on the optimistic side, you are right, they would have known before March that guidance was shot.
It's a first strike against these guys for transparency and expectation management.
On the plus side, no grade/geological issues.
Not sure if anyone believed $1000 would be achievable immediately after full tonnages had been reached. Maybe with some further optimization they can get there. Still very good margins and cashflow at those costs.
If the share price were to get knocked significantly then I think this is probably a decent buying opportunity. remember A$ gold is $1850. DCN had already been falling compared to peer stocks like GOR/RMS/SLR which had run hard in the last few weeks. Downgrade looks like it was priced in.
DCN Price at posting:
$2.45 Sentiment: Buy Disclosure: Held