Medusa Mining has more than doubled the probable ore reserve estimates at its Co-O Mine in the Philippines, following a JORC compliant ore reserve estimation.

The new estimate puts the reserves at more than one million tonnes at 14.9 g/t gold containing 500,000oz of gold, Medusa subsidiary Philsaga Mining said.

The previous estimate, announced in August 2008, was 249,000oz at 10.08 g/t gold.

Based on the new ore reserves, the company expects the mine life to be five years with an annual production rate of 100,000oz a year.

As of 1 July, the mine had an indicated and inferred resource of 1.4 million ounces at a grade of 10.8 g/t of gold.

Medusa Managing director Geoff Davis said the mine life of five years is a major achievement for a narrow vein mine.

“[It] is the culmination of over 40,000m of drilling and over 6,000m of underground development that has been completed during the last year,” Davis said.