New estimate boosts global resources at Angostura

Vancouver A newly released independent study has boosted global resources at Greystar Resources’ (GSL-T) wholly owned Angostura gold-silver deposit in northeastern Colombia.

Total indicated resources now stand at 148.1 million tonnes grading 1.22 grams gold and 51.7 grams silver per tonne, while inferred resources stand at 123.3 million tonnes of 1.13 grams gold and 5.42 grams silver. The new estimate is based on 111,328 metres of drilling in 366 holes, compared with 96,627 metres in 315 holes used in a study released this spring. The deposit remains open in all directions.

The previous study estimated that Angostura hosted an indicated resource of 87.26 million tonnes grading 1.23 grams gold and 5.2 grams silver, plus an additional inferred resource of 111.51 million tonnes grading 1.26 grams gold and 4.7 grams silver.

Oxide resources stand at 33.4 million tonnes grading 1.15 grams gold and 6.56 grams silver in the indicated category (containing about 1.2 million oz. gold and 14.5 million oz. silver), plus an additional 14.5 million tonnes of 1.09 grams gold and 6.11 grams silver in the inferred category. The new estimates use a 0.4-gram cutoff for oxides and a 0.55-gram cutoff grade for sulphides.

Greystar notes that the latest estimate “has not been constrained by the consideration of any mining, metallurgical or economic parameters.” The company envisions an open-pit mine at Angostura, and says gold recoveries in the oxide zone (roughly the top 100 metres of the deposit) should be “excellent” using heap-leach technology.

Metallurgical testing is continuing, as the deposit hosts different styles of mineralization both vertically and locally. Below the oxides are shallow sulphide and deep sulphide mineralization, while locally the gold is hosted in a series of vein structures that contain varying mineralogy at specific locations.

Greystar plans to spend $12 million at Angostura this year. Drilling is continuing, with nine rigs on site. The company also notes that a preliminary assessment will be required to determine which mining method and economic parameters are applicable to project’s resources.