Simplify the following text for a Grade 4 native English-speaking person.
Original: The mines were acquired by Anglo American U.B. Teader mining company in 1867 , which sold them to Moctezuma Copper Co , a subsidiary of Phelps Dodge .
Simplified: The mines were owned by the Anglo American U.B. Teader mining company in 1867 . They later sold them to the Moctezuma Copper Co. , which part of the Phelps Dodge company .