DanSome answers to your questions:0) is DMT (unit) equivalent to...

Dan
Some answers to your questions:
0) is DMT (unit) equivalent to BCM (unit)
DMT = dry metric tonnes, BCM is usually referred to as Bank Cubic Metres, i.e. the excavated volume. BCM contain moisture.
1) for this Q, does ore milled just become a subset of ore mined - is 218k BCM more than 129k DMT
Yes and Yes (assuming there is some moisture in the "as mined" ore), although the ore milled may have come from one or more stockpiles
2) if 1) is yes, how can in June Q can there be 31k ore mined, but 138k ore milled (prev stockpiles?)
The "excess" is ore drawn from stockpiles. Stockpiling is a way of smoothing out varying rates of ore deliveries.
3) if the price of gold went way up, are the tails (I guess leftovers, that means) re-millable to obtain more gold
Leftovers is a good non-technical term! Yes the small amount of gold will in theory increase in value, but whether or not it can be recovered profitably will be the question, e.g. the gold may be "locked" in grains of another mineral which would require finer grinding than originally undertaken or (and much harder to deal with) the residual may be locked in sulphides such as pyrite.
4) why are royalties per oz less in this Q
Royalties are directly proportional to gold produced; less gold = less royalties.
5) Is the head grade of 2 g/t repeatable through the mine life
It will vary with the grade of the ore mined during any particular quarter, however the schedule is likely to have been setup up to try and smooth out wide fluctuations as this makes keeping a relatively consistent feed to the mill easier to achieve.
6) the recovery was better this Q than March; is that to be expected going forward
Again depends upon the characteristics of the ore being fed to the mill and the increasing knowledge that the mill operators are gaining over time. If the ore stays much the same then the recovery "should" stay about the same, however the mets will always be looking for improvements!
7) given almost 7.5k recovered this Q, is there any reason to 'not hope for' 30k pa going forward
If the feed grade stays the same, recovery the same or better, and throughput the same or better ( better would be good!) then I guess the answer is probably. Of course if there is a sticky batch of ore, a breakdown in the mill, or one of a myriad other things that might happen, then perhaps output would be lower.
8) if ore mined is more then ore milled, does that mean a stock pile of high grade (2 g/t) is being built up; is the operation mining more dirt than it can mill
Yes the stockpile is growing. This could be due to a number of reasons: just in time mining is a potentially fraught process, the ore is needed for blending with "lower grade" ore at a later time, the stockpile needs to be larger to assist with a higher throughput (which would be good!) or simply it costs too much to have the mining fleet stand idle when there is ore or waste to be moved.

Hope this is helpful - of course AIMHO, others may be able to elaborate further.