LONDON, Nov 15 (Reuters) - Rio Tinto on Wednesday dismissed the former head of its aluminium division Ivan Vella with immediate effect, an email to all employees sent by CEO Jakob Stausholm and seen by Reuters showed.

Vella, who has spent two decades at the mining giant, was already due to leave the company in December, Rio had said in June, to become CEO of Australian battery minerals producer IGO Ltd.

He continued to lead the aluminium business until his successor Jerome Pecresse started on Oct. 23. In the weeks to Nov. 15, the contract termination date, Vella was supporting Pecresse in his new role.

"The termination relates to actions that did not follow Rio Tinto's guidance on acceptable management of confidential information," the internal communication email said.

Reuters does not know what the confidential information relates to.

Rio Tinto confirmed the content of the email and said it has "not identified that any information has been compromised."

"The first stage of our external investigation has concluded that Ivan failed to maintain the standards expected of him relating to this topic," the internal communication email added.

Both Vella and IGO could not immediately be reached for comment.

(Reporting by Clara Denina Editing by Marguerita Choy)