UPDATE 1-Glencore outbids Yancoal for Rio Tinto coal mines in Hunter Valley

LONDON, June 9 (Reuters) - Glencore on Friday said it had bid for coal mines owned by Rio Tinto in Hunter Valley, Australia, offering $2.55 billion cash plus a coal price linked royalty, outbidding a previous offer from Yancoal.

In January, Rio said it was selling its interest in Coal & Allied Industries Limited to Yancoal Australia Limited for $2.45 billion.

The terms of the deal allowed Rio to engage in negotiations with another party if Rio's board found "a competing proposal is (or is reasonably likely to become) a superior proposal," Glencore said.

It said its proposal, which was $100 million greater, met the criteria.

Glencore said the proposal would be funded from existing cash resources and committed facilities, although it also said there was no certainty a deal would be agreed. (Reporting by Barbara Lewis in London and Sanjeeban Sarkar in Bengaluru; Editing by Elaine Hardcastle)