Ivanhoe Australia announces Mount Dore mineral Resource increases by 35%

Ivanhoe Australia (ASX: IVA) announced today that an Independent Mineral Resource estimate for Mount Dore has increased the size of the copper deposit by 35%.

Mount Dore’s total Identified Mineral Resource estimate, based on a JORC equivalent estimate, at 0.25% Cu cut-off is 108 million tonnes at 0.6% copper, 0.2% zinc, 0.1 g/t gold, 87 ppm cobalt and 6.0 g/t silver.

This resource contains both secondary and primary mineralisation and is categorised as 53 million tonnes of secondary mineralisation at 0.65% copper which is amenable to heap leaching and 55 million tonnes of primary mineralisation which forms the basis of the Mount Dore polymetallic Mineral Resource.

With the updated Mount Dore Resource estimate the currently defined Mount Dore system, including the Merlin deposit, now contains almost 140 million tonnes of Mineral Resources in three separate projects.

Chief executive Peter Reeve said all the projects continued to demonstrate the potential for resource upside.

“During 2008 and 2009 the Mount Dore geological system was reappraised with a much broader geological perspective and since that time the growth in Mineral Resources on the Mount Dore system has been very significant”, Mr Reeve said.

“We will now work hard to establish the parameters for a second development project on the Mount Dore system with a copper heap leach, SXEW project following our success with the preliminary definition of the Merlin molybdenum and rhenium project."

The estimate of Mount Dore’s total contained metal in both the copper and polymetallic projects is 610,000 tonnes (1,340 million pounds) of copper, 240,000 tonnes of zinc, 360,000 ounces of gold and 21 million ounces of silver.

Of this, the Mount Dore SXEW heap leach project would have a total contained metal inventory of approximately 340,000 tonnes of copper.

In 2008 Ivanhoe Australia commenced a series of studies into the potential to recover copper from the copper oxides and transitional sulphides by open pit mining and conventional heap leach, SXEW methods. With the focus on the Merlin project these studies were deferred pending completion of the column leach testwork.

This updated resource estimate incorporates results of an additional 56 RC holes and 89 diamond drill holes from the 2008 estimate, however drilling has yet to be completed on the southern end of the deposit as rigs were diverted to the Merlin campaign.

The Mount Dore mineralisation now stretches for over 2.5 kilometres along strike and continues north over the top of the Merlin mineralisation and down dip to the east.

The Mount Dore Polymetallic Mineral Resource, which encapsulates the deeper sulphide mineralisation in the system, remains open at depth and to the north east and has been “incidentally” defined during drilling of Merlin.

“Mount Dore is revealing itself as quite an extraordinary geological system and as the resource base continues to grow it has the potential to provide Ivanhoe Australia with a series of operating projects” Mr Reeve said.

Work continues on the update for Swan/Mount Elliott Mineral Resource with a strong emphasis on the Swan High-Grade Zone (HGZ).

The Mineral Resource update is currently being completed by Australian Mining Consultants (AMC), Melbourne and will be NI 43-101 compliant for Canadian reporting purposes.

The initially declared Mineral Resource at 0.25% copper equivalent cut-off was 475 million tonnes at 0.5% copper and 0.3 g/t gold, and significantly, contains over 3 million tonnes copper and 5 million ounces gold.

It is currently contemplated that the Swan/Mount Elliott Mineral Resource update will be completed by January 2010.