Oct 10 (Reuters) - Rio Tinto Plc RIO.L
* Rio tinto to reduce gross debt by $1.5 billion
* To reduce gross debt by $1.5 billion through september cash tender offers
* Offer, which commenced on Sept. 26 2016 and will expire on Oct. 24 2016, was oversubscribed
* Approximately $1.5 billion of securities will be purchased Source text for Eikon: Further company coverage: RIO.L