I like the general idea, although a few of the names don't quite seem to fit.
I would suggest "Oreless" and "Mostly Oreless" for the first two ranks instead of "Mineless" and "Mostly Mineless". Instead of implying that the player is not in possession of mines, these titles should imply that the player is not in possession of the end product of mining (ore) similar to how the trade ranks "Penniless" and "Mostly Penniless" imply that the player is not in possession of the end product of trading goods (namely money).
"Digger" seems a bit odd to me since it implies the use of shovels. I would suggest the use of "Borer" instead to signify the use of drills
"Deep Core Miner" is a bit of a mouthful. Instead I would suggest the use of "Blaster", since this is exactly what deep core mining entails