News: RIO UPDATE 1-Rio Tinto declares $9.1 bln in dividends as first-half earnings more than double

(Adds background on iron ore demand, dividend)

July 28 (Reuters) - Rio Tinto (RIO) said on Wednesday first-half underlying earnings more than doubled due to a surge in iron ore prices on strong demand from China, prompting the global miner to return $9.1 billion in dividends.

A massive infrastructure push by China, the world's top iron ore consumer, and supply issues in Brazil helped prices of the commodity scale record highs earlier this year.

Rio, the world's top producer of iron ore, said average realised price for the commodity nearly doubled to $168.4 per dry metric tonne free on board from the same period a year earlier.

That surge in prices helped drive the miner's underlying earnings to $12.17 billion from $4.75 billion a year earlier. It beat a consensus of $12.01 billion from 14 analysts compiled by Vuma.

The company declared a special dividend of $1.85 per share, and an interim dividend of $3.76 per share, compared with last year's total payout of $1.55 for the first half.