Aquila's flagship Back Forty Project is a volcanogenic massive sulfide (VMS) deposit located along the mineral-rich Penokean Volcanic Belt in Michigan's Upper Peninsula. In its updated Preliminary Economic Assessment filed in September 2014, Back Forty demonstrated strong economics with a pre-tax NPV of $282 million ($210.8 million after-tax) and a pre-tax IRR of 38.8% (32% after-tax) based on mining 16.1M tonnes of measured, indicated, and inferred resources over the 16-year life of mine, of which 12.5M tonne will be open-pit and 3.6M tonnes will be underground.