Simplify the following text for a Grade 11 native English-speaking person.
Original: He and his father became minority owners of the Burnham Exploration Company , incorporated in 1919 by Harris Hays Hammond ( the son of John Hays Hammond , Sr ) .
Simplified: He and his father worked for the Burnham Exploration Company , incorporated in 1919 by Harris Hays Hammond ( the son of John Hays Hammond , Sr ) .