Prel. Economic Assessment: 300,000 oz of gold annually The updated preliminary economic assessment for Windfall, completed this month, outlines seven initial years of production averaging 300,000 oz. of gold annually from ore with a diluted grade of 8.1 g/t gold. Average after tax free cash flow is estimated to be C$253 million in each of the first seven years. The all-in sustaining cost of $610 per oz. gold produced. The capital cost of building the mine and mill will be C$544 million (including a power line and contingency)