Having overcome a few setbacks,
The celebration follows several weeks of delays caused by Hurricane Mitch and engineering changes to the conveyor and electrical distribution systems. Despite these problems, Greenstone reports that 250 oz. gold are now being poured daily, with the targeted monthly rate of 15,000 oz. expected to be reached by mid-year.
Production for 1999 is expected to total 117,000 oz., with cash costs pegged at US$120 per oz. At full speed, San Andres is expected to crank out 180,000 oz. yearly from its proven and probable reserves of 22.3 million tonnes grading 1.11 grams gold.
Mining of higher-grade pockets is expected to keep head grades above 1.5 grams in the first two years of operations, and the company says such grades can be prolonged if, as expected, additional high-grade reserves are outlined. Probable reserves stand at 476,000 tonnes grading 0.83 gram.
Currently, 10,500 tonnes are being contract-mined daily, and this rate is expected to rise to 21,000 tonnes by June. To date, Greenstone has mined a total of 441,000 tonnes averaging 1.67 grams gold per tonne, for which only 220,500 tonnes of waste were removed. Of this, 267,000 tonnes of ore containing 16,820 oz. have been stacked on the leach pads, with the remaining 174,000 tonnes containing 6,850 oz. stockpiled. Another 40,000 tonnes containing 10,000 oz., which was discovered during pit excavation, are being processed separately, and 80% of the ore currently stacked is under leach.
Both the primary and secondary crushers are operating, as is the drum agglomerator and 1-km-long conveying system. Ore is being delivered and stacked on the leach pad at or above daily rates required to meet the company’s near-term production targets.
Metallurgical aspects also appear positive, with no surprises foreseen with agglomeration. Solution grades fed to the carbon adsorption-desorption recovery plant have averaged 2.5 grams per tonne of solution, with a total of 2,615 oz. gold reporting to carbon from the heaps in the first 13 days of operations.
San Andres is Greenstone’s second-largest project, next to the Cerro Mojon open-pit heap-leach mine in Nicaragua, where proven and probable reserves stand at 17.62 million tonnes grading 2.14 grams gold. Similar-type material at the company’s Bonanza underground mine, also in Nicaragua, is pegged at 229,000 tonnes grading 7.61 grams gold, whereas reserves at the Santa Rosa open-pit heap-leach mine in Panama total 5.07 million tonnes grading 1.9 grams gold. (Mining at Santa Rosa was recently suspended in order to improve cash flow, but leaching continues.) Combined, the four host possible reserves of 5.9 million tonnes averaging 2.22 grams. All reserve calculations are based on a gold price of US$300 per oz.
As of Dec. 31, Greenstone’s total combined resources at its operations stood at 132.7 million tonnes averaging 1.38 grams gold. These were calculated using the same cutoff grade applied to reserve estimations.
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