Feb 24 2011
Robert Friedland, Chairman, and Peter Reeve, Chief Executive Officer of Ivanhoe Australia Limited (TSX:IVA)(ASX:IVA), has announced that the Starra Line drilling program, on Ivanhoe Australia's Cloncurry tenements in northwestern Queensland, has intersected further high-grade copper-gold mineralisation adjacent to the existing Mineral Resource at the gold-rich Starra 222 ore body.
These drilling results follow on from the recent high-grade results in hole STQ1036 and extend the mineralised zone up-plunge by at least 200 metres. This high-grade mineralised zone in Starra 222, which forms an important part of the Osborne Copper Gold Study plan, has a true thickness of between 5 to 30 metres and a strike-length of at least 250 metres. The mineralised zone is adjacent to the developed Starra 222 decline and is open below the existing drilling results.
STQ1042, the fifth hole drilled by Ivanhoe Australia at Starra 222, intersected the following high-grade gold mineralisation
STQ1042 – 19.4 metres @ 1.98% copper and 4.27 g/t gold from 384.6 metres, including 13 metres @ 2.92% copper and 3.9 g/t gold from 390 metres; and including 1.4 metres @ 0.06% copper and 21.1 g/t gold from 384.6 metres.
"These high-grade gold results are important because they are expected to lead to a significant increase in the resources contained at Starra 222," Mr Reeve said.
"As the Starra mineralised system is adjacent to the planned Osborne-Merlin haul road and contains similar copper-gold mineralisation to the Osborne Deposit, the resource upgrade will be key to Ivanhoe Australia's strategy of identifying nearby sources of ore for the Osborne mill complex.
"Our ability to economically mine the Starra 222 resources is greatly enhanced by the existing decline. The decline was inspected by Ivanhoe mining engineers in December 2010 who found it to be in good working condition.
"The Starra Line is significantly underexplored, having been subject only to limited shallow drilling. Ivanhoe Australia believes there is strong potential for further discoveries along the line's 52-kilometre length, demonstrated by Barrick's earlier discovery of the Lucky Luke Deposit located on the Starra Line nine kilometres south of the Starra 222 Mine."
The results from hole STQ1042, which targeted the along-strike extension of the deposit's most northern mineralisation, indicate that copper-gold mineralisation at Starra 222 remains open 200 metres up-plunge of recent drilling. These mineralised ironstones are located 220 metres north of the base of the Starra 222 decline and 30 to 70 metres north of the existing Starra Mineral Resource (QG, 2008).
The independent JORC-compliant Mineral Resource estimate for Starra 222 utilising a 0.5% eCu cut off, released in 2008 by Quantitative Group (QG), prior to Ivanhoe Australia commencing detailed work along the Starra line, was:
This 2008 QG resource estimate was not 43-101 compliant as historic data was not reviewed in detail. Ivanhoe Australia's development team is planning further drilling on Starra 222 to test the potential northern extensions of the mineralisation and produce a NI-43 101 compliant Mineral Resource estimate. This drilling program will commence once the current resource definition drilling underway at Starra 276 has been completed.
Mineralisation at Starra 222 is hosted within magnetite ironstones that have been strongly hematite-altered, with gold grades increasing with the degree of hematite alteration. The drilling at 222 has yet to test the full depth of the IOCG system, which is estimated from recent geophysical surveys to be at least two kilometres deep.
Starra Line history
The Starra Line is a 52-kilometre-long regional structure that is strongly magnetite altered and hosts widespread copper-gold mineralisation. The six-kilometre section of this structure exposed in the Selwyn region hosts five mines that produced approximately 170,000 tonnes of copper and one million ounces of gold from 6.8 million tonnes of ore @ 2.1% copper and 4.6 grams of gold per tone between 1987 and 2002.
Starra 222 is particularly gold-rich and produced 290,000 ounces of gold and 22,000 tonnes of copper from 2.2 million tonnes of ore @ 1.0 % copper and 4.1 grams of gold per tonne. Significant resources remained when mining ceased at Starra 222 in 2002. Ivanhoe commenced drilling at Starra 222 in August 2010.
The remaining 46 kilometres of the Starra Line lie under approximately 5 to 50 metres of cover; approximately 10 kilometres of this strike are north of Starra 276 and the remaining 36 kilometres are south of Starra 222.
Source: Ivanhoe Australia Limited