Intrepid Advances Tujuh Bukit Project

Intrepid Mines reported in May 2011 that assay results from drilling completed since September 2010
around the known porphyry copper-gold zone of the Tumpangpitu area of the Tujuh Bukit project in Indonesia
provided an expanded Inferred Resource estimated at 990 million mt at 0.4% copper and 0.45 g/mt gold,
at a cutoff grade of 0.2% copper or 0.2 g/mt gold. (Photo courtesy of Intrepid Mines)

Intrepid Mines has reported the results of a preliminary economic assessment (PEA) for a potential open-pit, heap-leach gold project on the oxide resource at the Tujuh Bukit project in the far southeast of the island of Java, Indonesia.

Intrepid, an Australian company based in Brisbane, has an 80% interest in the project; PT Indo Multi Niaga, an Indonesian company, holds the remainder. Kappes Cassiday prepared the PEA based on column leach and other metallurgical tests performed at its laboratory in Reno, Nevada, USA. The PEA considered only the near-surface oxide resource at Tujuh Bukit and not the far-larger underlying porphyry resources.

The PEA postulates production of 143,000 oz/y of gold over a nine-year mine life at a cash cost of $376/oz, net of silver credits. Mine production would total 57 million mt grading 0.83 g/mt gold and 23 g/mt silver over the life of the project. Mill feed would average 20,000 mt/d. Preproduction capital cost, assuming contract mining, is estimated at $204 million. Processing would include a conventional cyanide heap leach followed by Merrill Crowe precipitation and smelting to produce gold-silver doré on site.

Intrepid's board of directors has approved work necessary to support a prefeasibility study, including in-fill drilling, additional metallurgical test work, engineering design and financing evaluation. The forestry approval process will be conducted in parallel with this work.

As featured in Womp 2011 Vol 05 -