I have a very unexpected new favorite hobby: building new mines.
I have 4 in my world now(SP, day 37, 120 min days, Navezgane) and each one is unique.
I seriously had so much fun building each one, the choose-a-block menu is such a huge QOL improvement for more than just the block shapes, heading into a new mine with a stack of catwalks and logs(support beams) gets me excited now. The walkways and supports I build along the way are both useful and super neat looking afterward, makes them all feel like legit mines.
And it's not just the awesome system building upgrade, it's also the way the new ores work. I've made a habit of clearing out the sand within a deposit first thing, once that is done the mines are so freakin neat looking I almost don't want to mine it out... almost

End up with such cool looking caverns, the new ore textures are so well done.
And yes multi-mines rock. Took me forever to find a nitrate deposit in the forest biome, finally found one and immediately noticed I was in the rad zone, of course. But nearby I found not one but two nitrate rocks near each other, built a large mine between them, and now aside from being buried in nitrate I found an iron seam in it too that I've spent multiple nights pounding on and still have yet to diminish.
Made a super cool low profile mine entrance for my oil shale mine in the desert... nvm that I turned on CM for the first and only time in this game just to spawn a second tablesaw(always make my first legit) just so I could make the wood wedges I needed. Please, please add the wedge to the menu, spoiled an otherwise CM free game(which is a good thing overall for this alpha imho). Anyway that mine is super neat, walls of oil shale are so sweet looking, took some furniture helpers and made myself a sweet little home-away-from-home in a pocket of shale for the long nights I spend there.
My coal mine is the cutest tiniest little cabin made all out of logs on the surface snow that turns into an elaborate deep super mine below, so cool.
And I never, ever, mine the initial surface rock, usually surround it in bars to protect it, make my building/entrance around/down from there. Serves as a great entrance piece and obvious label for that deposit.
That's it, just a major shout out for Mining in A18. I had no idea I would be so impressed by these changes, it rly is one of my new fav things now. Kudos TFP.