* Company names vice chairman as interim CEO
* Shares fall 8 percent after the bell
Dec 11 (Reuters) - Rare earth producer Molycorp Inc said Chief Executive Mark Smith has quit, a month after the company revealed that it was under investigation by U.S. securities regulators over the accuracy of its public disclosures.
Shares of the company fell 8 percent to $10.40 in extended trading on Tuesday. The stock has more than halved in the past year.
Smith became the CEO of Molycorp in October 2008, overseeing its C$1.2 billion acquisition of Neo Material Technologies and the ramp up of its production capacity.
Prices of rare earth elements, however, have tumbled because new supplies have hit the market and top producer China has raised exports.
As Molycorp transitions from a development-stage company to an operational one, a different style of management was needed to run it, spokesman Jim Sims said.
He said there was no connection between Smith's exit and the probe by the Securities and Exchange Commission.
Molycorp on Tuesday named Constantine Karayannopoulos, vice chairman of its board who was previously the CEO of Neo Material, as the interim president and chief executive.
Greenwood Village, Colorado-based Molycorp said it was immediately undertaking a search for a permanent CEO.