The Lost Mine is a short story by Agatha Christie which was first published in The Sketch in November 1923 in the U.K. In the U.S., the story was first published in The Blue Book Magazine also in April 1925. The story was gathered and included in the U.S. edition of the collection Poirot Investigates published by Dodd, Mead and Company in the U.S. in 1925. In the U.K., the story was not anthologized until it was included in Poirot's Early Cases in 1974.