Mr Skinner announced his retirement from the Rio Tinto (rio.ASX:Quote,News) board in October amid the throes of a hostile takeover from rival BHP Billiton (bhp.ASX:Quote,News), with the chairman expected to see out his tenure till December 2009.
However, Rio Tinto announced in January that Mr Leng, deputy chairman of Tata Steel Ltd in India, would take over the role after the company's Australian annual general meeting on April 20.
Mr Leng was appointed to the board as a non-executive director and chairman-designate.
"Rio Tinto announces that Jim Leng, a non-executive Director, has resigned from the Boards with immediate effect and will therefore not take up the post of Chairman of the Boards in April as previously planned,'' the company said in a statement.
Rio Tinto said Mr Skinner would remain as chairman until mid-2009, by which time it is anticipated that a successor would be appointed.
Mr Skinner, 63, was appointed to the Rio Tinto board as a director in 2001 before being elevated to chairman in 2003.
It is believed that Mr Skinner, who was previously group managing director of the Royal Dutch/Shell Group of Companies, is up for the chairman role at oil major BP Global when Peter Sutherland steps down this year.
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