Karayannopoulos succeeds Mark A.Smith, who has left the company.
Constantine Karayannopoulos will assume all management responsibilities for Molycorp and its subsidiaries, effective immediately, and will continue to serve as a director and the vice chairman of Molycorp's board. A professional engineer, Karayannopoulos previously served as president and CEO of Neo Material Technologies, a position he held from 2005 until this year. At Neo Materials Technologies, Karayannopoulos also served as executive vice president and chief operating officer, as well as vice president and general manager of the company's rare earths business unit and vice-president of sales.
"The board of directors thanks Mark Smith for his significant contributions and leadership over the past four years that have brought Molycorp to this natural transition into an ongoing operating business, and we wish him well in his future endeavours," said Ross R Bhappu, chairman of the board. "Looking ahead, we have full faith and confidence in Constantine to manage the company, operating with the best people and assets in the industry."