A better and safer version is to drink just every time she says "I." Sometimes grammar forces us to use 1st person pronouns when ourselves are not necessarily the topic. See how many times I used a 1st person pronoun in the last sentence when I was discussing grammar?
I, however, is the subject form of the 1st person pronoun, so every time the subject is herself, drink.
hmm. true. guess she could be talking about an actual mine as well. Like "I have to live in a mine because the townsfolk keep chasing me away because of my fuckin' ears"