BHP Billiton Ltd is expected to reveal a major increase in the resource estimate at it Olympic Dam copper/uranium orebody in South Australia, reported the Age newspaper without citing sources.

The new resource estimate for the deposit is expected to be included in BHP's 2005-06 annual report, due to be released in the week starting Sept 18, according to the report.

The resource estimate was last updated in 2004.

Even without the expected increase, Olympic Dam already ranks as the world's fifth biggest copper resource and the number one uranium deposit.

While the resource upgrade would push the deposit up the ranks of copper deposits, the Age said it is the expected hike in the uranium resources that will create most interest.

Olympic Dam already accounts for 40 pct of the world's known uranium resources, with 1.524 mln metric tons of the radioactive material.

The newspaper said since acquiring the project's former owner WMC Resources Ltd last year for 9.2 bln aud, BHP has carried on with the aggressive drilling program involving 18 drill rigs aimed at determining the size of Olympic Dam.

Results from the drilling are being fed into a pre-feasibility study, due to be completed at the end of 2007, which assesses a 7-10 bln aud expansion of Olympic Dam that would triple current annual production of copper and uranium to 600,000 tons and 15,000 tons respectively.