Translation:The study takes at least three years.
I always translate in my head "dauern" as "durate" and then try to translate "durate" into a word that most people in English will use. It's not a very effective strategy. "The study durates at least three years."
The study has a duration of at least three years - Das Studium hat eine Dauer von mindestens drei Jahren.
Does this mean "the study" like a piece of research (e.g. "I'm doing a study on how people acquire second language sounds")?
According to Wiktionary, it's the act of studying (presumably, in the context of this sentence, for a qualification of some kind).
To be honest, I don't think that 'study' is a good translation here. I'd prefer 'course'.