Team Logo. The Thetford Mines Pirates were a team in the Eastern League. They were the AA affiliate of the Pittsburgh Pirates. In 1976 they moved to Pennsylvania and became the Williamsport Bills. Retrieved from "https://prosportsteams.fandom.com/wiki/Thetford_Mines_Pirates?oldid=7493" Categories: Former EL Teams Teams in Quebec Add category Cancel Save Community content is available under CC-BY-SA unless otherwise noted.