Getting 85 mining depends on a couple of things. Is this account a level 3 fresh off tutorial island, or is this account like a main account with 2k+ total?
These small facts are often times important because the more progressed an account is, the less ban chance you have during botting.
Although this is risky to do, I personally would maybe run a script that does a few quests, then mines for a full session like 4+ hours, then maybe take a break and then return to bot some skilling.
Ultimately, the more random activities you include into botting, the less ban chance you have - regardless of breaks.