First i want to say, that i really dig the new mining. The new rock types are awesome and make mining a lot more diverse than it has been. I think mining has a TON of untapped potential and is now an even more of a worthwhile activity apart from mining mere metals.
I want to suggest more mining events - i know you probably have some of them already on your list *trolls* but here are some more ideas.
I would love to see Dinosaur skeletons that spread over multiple tiles.
Also cool would be for example treasure chests, roots, rabbitholes, moles and maybe ancient burial sites where you could dig out weapons with different models or uncover skulls of different qualities also those events could be possibly tied to certain rock types. Also it could be nice to uncover remnants of old civilizations, like past worlds? Maybe Stone tablets talking about some past historic places.