Nice to have a lively discussion on the DCN threads.
I will keep it short.
Overall agree with Quester, most of the costs DCN include each day/week/month/quater, are fixed (or very similar).
Fuel prices fluctuate a little. Overtime can peak and trough, but the plant costs $$ per day. Energy costs $$ per day.
Staffing, would usually stay fairly static $$
Mining costs fairly static, though.... all mining get away with quite a bit of flexibility on stripping costs and what is sustaining, and non-sustaining.
I will use another company I hold (had a tough week last week I might add).
AISC over the past 12 months has averaged around $1300, a great result, yet.... it also had over $60m in non-sustaining costs (bloody big amount of stripping basically), which caused their AIC to be closer to $2160 AUD.
DCN has basically been in the same boat, though I think they have had to massage their mine plan a bit more (GCY has 1 single pit), due to what I assume, is ore access issues, and, if another post is right, maybe a small issue with DoubleJays grades.
In either case, higher production, means a lower AISC, but... not necessarily a much lower AIC (though it would logically be somewhat lower).
As for the treatment of low grade stock piles, sure, there are very little costs to mining it, but, processing costs are still there, and... it's low grade, so, the amount of ounces is much much lower.
i..e GCY has in it mines plan, 3 full years of production at 30k p.a, just treating the huge amount of low grade ore they siphoned off to treat the higher grade ore. The AISC for those years are around $1800 AUD.... non-nonsustaining costs though. So, it will still be profitable, but... nothing exiting.
If DCN really could treat and profit handsomely from its low grade stock pile, versus another capital raising, I assume they would have done it. As that would have enabled them a lot of flexibility to get ahead with the current mine plan, yet they did not. Hence, it would be barely profitable currently.
Companies like DCN/GCY and others, are, inherently, high risk. Their lower production profile, low grades and single plant asset ensure this. Then it all comes down to the mine plan and the grade. Both GCY and DCN had a relatively good 12 months or so, yet... when a snag is hit, oh damn does it hurt. 1 or 2 bad quarters, and the companies are much less able to bounce back.
Anyway, good luck to all holders. I hope DCN are able to meed guidance!