Does the Pots O' Gold bonus from the Abyss Bar drink yield the mining bonus for gold that you "collapse" by mining behind or just gold that you mine by hitting directly? Asking because I just exploded a Glyphid Crassus Detonator :-)
If I understand correctly, that by "collapsing" you mean mining all support of a piece of terrain, making it instantaneously break, then unfortunately no.
Pots O' Gold works by multiplying any gold drops from broken terrain mined directly by your pickaxe. Collapsed terrain, terrain destroyed by explosions or weapons or terrain mined by Bosco doesn't drop any extra gold. I tested this extensively - mining around a gold vein with Power Drills didn't yield any extra drops, neither did destroying the last piece of support with the pickaxe. Further mention of this can be found on the DRG wiki, so that you don't have to take just my word for it.
Of course, hitting the terrain directly behind the gold with your pickaxe, so that some of the gold is mined along with the terrain, still counts as "being mined by the pickaxe". It's not important whether it's the terrain, or the gold, that you're directly hitting - as long as any of the gold is part of the area destroyed by your pickaxe, the drop gets multiplied.