Results from 41 diamond drill holes at G-Resources’ Horas deposit have led to an updated resource estimate to include 400,000 ounces of gold at an average grade of 0.8 grams/tonne and 880,000 ounces of silver at 1.7 grams/tonne. It’s the last of three resource estimates for 2011 aimed at defining the Purnama Timur, Tor Uluala and Horas deposits at the company’s Martabe project in North Sumatra.
The Martabe licence area covers 1639sqkm with a resource base to date of 7.86 million ounces of gold and 73.48 million ounces of silver. G-Resources acquired the gold and silver mine in July 2009 as its core starter asset, which it hopes to build a globally competitive Asia-Pacific focused gold company around.
A team of 15 geologists and five helicopter supported diamond drill rigs are engaged in drilling programs across the projects, with staff working to generate and test exploration targets for both epithermal gold/silver and porphyry copper/gold mineralization.
Gold-silver mineralization at Martabe comprises a higher grade core with intense silicification and a lower grade halo with lower silicification and strong clay alteration. The Horas deposit outcrops at the surface and dips to the west with a strike length of about 600 metres and a known depth to 250 metres.
The high grade Horas Barat prospect to the west may represent a higher grade feeder zone or a parallel but separate gold-silver system.
Preliminary metallurgical analysis by independent geological and resource estimate consultants compared the ratio of cyanide soluble gold assay to gold by fire assay. G-Resources says the work indicates that the deposit is likely to be refractory because it is largely composed of primary mineralization style. Initial test work has indicated that recoveries of about 80% have been obtained on mineralization from the Purnama deposit, which has prompted the company to undertake further work to determine the optimal processing options for Horas.
Construction of the Martabe mine is already under way and G-Resources aims to start production at its Purnama Timur deposit in early 2012 at an annual rate of 250,000 ounces of gold and 2-3 million ounces of silver.
The company is hoping to increase production to more than one million ounces of gold annually by exploring the licence area and acquiring other quality gold assets. The Martabe project is also being supported by the local, central and provincial Indonesian governments and the nearby Batangtoru.