Thanks for the links.
Not sure if you want to correct my spelling of porphyry or clarify my assertion that Oyu Tolgoi is the largest such deposit known, or just want to share some info with the board...(;=))
The tables in the Gangue publication are very informative.
Since it was published in July of 2004, they would not have had the benefit of the latest resource estimates for Oyu Tolgoi though.
ivanhoe-mines.com
Also, the Gangue results don't provide a cutoff for the resource in these tables.
But, looking at their rankings of El Teniente as the largest porphyry deposit of contained Cu at 900+ Mt and Grasberg as the largest contained Au at about 2600 t, I think Oyu Tolgoi may well be larger.
"The Oyu Tolgoi Complex (Ivanhoe's 100% owned Oyu Tolgoi Property and the adjoining Ivanhoe/Entrée joint venture Shivee Property) now contains:
Proven and Probable open-pit reserves of 930 million tonnes, with a grade of 0.50% copper and 0.36 g/t gold, containing 8.9 billion pounds of recovered copper and 7.6 million ounces of recovered gold. The reserve estimate was prepared by GRD Minproc Limited in January 2006 (see Ivanhoe's January 30, 2006, news release) based on Net Smelter Return (NSR) cut-offs equal to a copper equivalent cut-off of 0.3%. The Southern Oyu resources are calculated at a copper equivalent cut-off of 0.3% in the GRD Minproc Mineral Reserve estimate.
Measured and Indicated resources, inclusive of Proven and Probable reserves, totalling 1.15 billion tonnes grading 1.27% copper and 0.48 g/t gold (a copper equivalent grade of 1.58%), containing 32.2 billion pounds of copper and 17.7 million ounces of gold, at a 0.60% copper equivalent cut-off grade.
And in addition, Inferred resources of 1.44 billion tonnes grading 1.11% copper and 0.28 g/t gold (a copper equivalent grade of 1.29%), containing approximately 35.3 billion pounds of copper and 13.1 million ounces of gold, at a 0.60% copper equivalent cut-off grade."
ivanhoe-mines.com
The northern limits of the ore body are still being defined..... |
