Indicated gold resources remain largely unchanged at Medusa Mining’s projects in northeast Mindanao, the Philippines, despite depletion due to mining in the past 12 months.
In its annual report Medusa said that it had mined 105,000 ounces in the year to June 30 but the amount still present in the indicated category was around the same and at a slightly higher grade. This is primarily due to the company’s emphasis on infill drilling which has converted inferred resources into the higher indicated category.
At the flagship Co-O mine, total inferred and indicated are estimated at 3.5 million tonnes @ 10.2 grams/tonne gold for a total 1.15 million ounces, compared to the 2014 estimate of 4.34 million tonnes @ 10.1 grams/tonne for a total of 1.41 million ounces.
At Bananghilig deposit total inferred and indicated resources are 24.52 million tonnes @ 1.44 grams/tonne and at Saugon there are 81,500 tonnes @ 5.97 grams/tonne. These yet to be mined deposits near Co-O remain unchanged from the 2013 estimate.
Medusa’s CEO Geoff Davis said the fact indicated resources were largely maintained at the previous year’s level validated the group’s emphasis on infill drilling. “Once the new reserve estimates are completed shortly, it is expected that the level of reserves should be maintained within the same range as the previous six years, a very consistent record.
“While inferred resources have reduced primarily through less extensional drilling to replace converted resources, it is planned that the drilling due to commence from Level 8 in the December quarter will be a combination of extensional and infill drilling. This should extend the resources to depth.”
At Co-O there has been a reduction of some interpreted vein thicknesses at depth in the inferred category based on vein development in the upper levels. There has also been the addition of a higher proportion of internal waste to reflect the discontinuous nature of some veins.
Improved survey practices have resulted in better stope definition while the availability of in-situ pillars has been revised due to mining access.