Major resource boost at Ivanhoe’s Oyu Tolgoi

Vancouver – A significant resource increase has been calculated for Ivanhoe Mines’ (IVN-T) Oyu Tolgoi copper-gold deposit, in the southern Gobi region of Mongolia.

The study by engineering firm AMEC reviews measured and indicated resources of 1.15 billion tonnes grading 1.3% copper and 0.47 gram gold per tonne (or a copper equivalent grade of 1.54%) at 0.6% copper equivalent cut-off grade.

The new measured and indicated calculation shows almost 15 million tonnes (about 33 billion pounds) of contained copper and 17.3 million oz. of contained gold in the deposit. Measured and indicated tonnage is up 125% from last year’s estimate and contained copper and gold are up 360% and 85% respectively.

Additional inferred resources of 1.16 billion tonnes of 1% copper and 0.23 gram gold (a copper equivalent grade of 1.16%) were also calculated using the same cut-off parameters. The inferred component’s metal content is a further 11.8 million tonnes (26 billion pounds) of copper and 8.4 million oz. of gold.

The bulk of Oyu Tolgoi’s resource increases have come from extensive infill and step-out drilling on the Hugo North deposit, significantly expanding the high-grade core of the copper-rich porphyry deposit. Hugo North now extends over a strike length greater than 1.8 km within the 3-plus-km-long Hugo Dummett deposit.

The Hugo Dummett deposit is a higher-grade, deeper portion of the Oyu Tolgoi project, holding indicated resources of 582 million tonnes at 1.9% copper and 0.4 gram gold. An additional inferred resource of 1.1 billion tonnes of 1.1% copper and 0.2 gram gold was also calculated.

AMEC’s resource estimates will be incorporated into Ivanhoe Mines’ Integrated Development Plan (IDP) scheduled for completion by mid-2005. The IDP will review planned development of the Oyu Tolgoi complex through combined open pit operations and large underground block cave mining.