I can’t find a general discussion thread for the v31 update, please feel free to move this.
Also don’t see this mentioned anywhere, so don’t know if this is a bug or new feature, but something different appeared with the update (just got it a couple hours ago).
Some numbers appeared over 2 of 3 running mines when they were ready to collect. All three were ready, but only 2 had numbers, and as you can see the numbers were varying degrees of faintness. Turns out that when I collected them, that number was the total iron ready for collection.
The third mine, without the hovering numbers (far fight in the pic) acted as it always has: the collection numbers appeared at the time of collection during the animation.
For the record: I like being able to see how much is there before collecting it, I really hope that was intended.
BUT, since all of the mines aren’t acting the same, something might be amiss somewhere. Or I’ve just been oblivious this whole time, which is unfortunately subject to rng, sorry 
Also curious if anyone else is seeing this after updating, seems like I would’ve seen mention of it but, again, I might’ve missed it.
[Edited to add: my farms came up for collection while I was posting this, none of them have the collection numbers visible before collecting.]
