Unfortunately, ArsMagica had to be removed: It turned out to be buggy, and there was a reported known bug with it crashing servers. It bypassed chunk claims and fixing that problem isn't, in our opinion, worth the trouble. Not a lot of gameplay time for a mod that's relatively big (10 MB). An update 13a was pushed which removes ArsMagica, and it is technically an optional update. Removing ArsMagica saves you a bit of memory, however. The mining world reset scheduled for May 4th is still going forward.
About the mining world reset. What's the reason for it?. Surely there isn't a reason to reset it if no world-gen adding mod is added.
Maybe to clean up the bores that are still just rotting, corrupted chunks, and hopefully I wont spawn in water again.
Yeah I think it's to remove those nasty bore holes. Plus it gives us a fresh new map which is always a good thing.