Avocet upgrades resource at North Lanut gold mine
Tuesday, December 11 2007 - 09:43 AM WIB
Avocet Mining PLC announces continued growth of the gold resource at its North Lanut gold mine in North Sulawesi, Indonesia. The increased resource follows the completion, and inclusion in the resource model, of 34 reverse circulation infill drill holes (3,585 metres) at the operation?s Riska. This upgrade to the Riska model is the latest step in the Company?s goal of extending the mine life at North Lanut.
The increased resource follows the completion, and inclusion in the resource model, of 34 reverse circulation infill drill holes (3,585 metres) at the operation?s Riska. This upgrade to the Riska model is the latest step in the company?s goal of extending the mine life at North Lanut, it said.
The revised Riska model has produced Measured, Indicated and Inferred Resources of 7.32 million tonnes with a grade of 1.44 g/t Au, above the economic cut-off of 0.3 g/t Au. This compares with the previous resource model dated 31 March 2007 of 9.07 million tonnes at a grade of 1.21g/t Au.
The total resource at Riska is now 337,900 ounces of gold with the updated resource representing an addition of 99,000 ounces of gold or 28% net of mined ounces depletion. This includes Inferred Resources of 1.87 million tonnes grading 1.31 g/t Au and containing 78,800 ounces of gold. These resources are classified according to the definitions outlined in the JORC Code of 2004 (Australasian Joint Ore Reserves Committee). The resource model is cut to the open pit topographic surface at the end of October 2007.
Avocet is currently conducting an open pit optimisation review at Riska using current costs and revenue parameters. The resulting optimal pit, which will be finalised shortly, will form the basis of a revised pit design and the reporting of Proven and Probable reserves.
The majority of the tonnes (74.5%) and ounces (76.7%) are Measured and Indicated. Most of the Inferred ounces occur at depth within the sulphide portion of the deposit or along the low grade periphery where the drill density is lower and the impact on contained ounces is less significant. It should be noted that the depletion figure of 114,700 ounces includes ounces that are in the process of leaching, a proportion of which are expected to report to production in the remainder of the financial year.
Further drilling will be carried out to fully define the resource in the core of the deposit and this may result in further upgrades to the resource at Riska as the current upward trending of the gold grade indicates that the resource model continues to underestimate contained gold in high grade ore zones. This is partly because of a sampling bias created by diamond drilling that does not adequately sample gold on fractures because of drill water flushing of the rock during drilling and core sampling. This is further compounded by the fact that the modelled high grade supergene zone at the base of the transition zone is much larger and higher grade then previously thought.
Following previous positive drilling at Effendi, located nearby to Riska, follow up drilling is ongoing. This will allow the Company to refine the geological model for the Effendi deposit, and to produce a revised resource in the coming months. The current JORC-compliant resource at Effendi, as stated in the Company?s 2007 annual report, shows an Indicated Resource of 117,500 ounces of gold and an Inferred Resource of 20,800 ounces.
Jonathan Henry, Chief Executive Officer, commented:
?The excellent drilling results previously announced have resulted in a significant upgrade to the resource at Riska and will allow us to extend the mine life at North Lanut. Further drilling at Riska will be carried out in due course to fully realise the upside potential of the deposit?s high grade core. An upgraded resource at both Riska and Effendi, combined with the strong operational performance at the mine, ensures North Lanut will remain our key asset in Indonesia and further solidifies our strong position in the region.?
The company has 80 percent stake in North Lanut mine.(end of edited excerpt)