UPDATE 1-Rio doubles planned capex for 2010

* Sees 2010 capex at $5-$6 bln, pvs forecast of $2.5 bln

* Cuts debt by 42 percent in 2009 to $22.3

* Boosts expansion plan for Australian iron ore

LONDON, Oct 30 - Mining group Rio Tinto has doubled its planned capital spending for next year to at least $5 billion after it cut debt and saw signs of economic recovery. Capital spending in 2010 was due to be cut to $2.5 billion, just enough to sustain current mines, but current plans were for $5-$6 billion, Rio said in a statement on Friday ahead of a briefing for investors later in the day.

"We will continue our programme of cost reduction and debt repayments, but our renewed strength enables us to focus on disciplined capital expenditure on premier growth options," Chief Executive Tom Albanese said.

Capex this year is expected to be around $5 billion.

Rio, the world's third biggest mining group by market value, also said it had cut its net debt by 42 percent so far this year to $22.3 billion by the end of September.

The group was on track to achieve operating cost savings of $2.5 billion next year, it added.

The group, the world's second biggest iron ore producer, also said it was pushing forward with plans to expand operations in the Pilbara in Western Australia to 330 million tonnes per year, up 10 million tonnes from its previous plan. Rio struck a positive but cautious note for a global recovery in minerals markets on Oct. 14 when it released third-quarter production data.