Augusta Announces 34% Increase in Rosemont Sulfide Mineral Resource

Augusta Resource Corporation AZC has completed an updated National Instrument ("NI") 43-101 compliant mineral resource for its Rosemont Copper project ("Rosemont") near Tucson, Arizona. The updated mineral resource estimate is comprised of: Measured and indicated sulfide mineral resources of 919 million tons, representing an increase of 232 million tons or 34% when compared to the 2008 mineral resource, with average grades of 0.41% copper and 0.014% molybdenum for a total of 7.5 billion lbs of copper and 256 million lbs of molybdenum; Inferred sulfide mineral resource of 139 million tons, representing a decrease of 106 million tons or 43% when compared to the 2008 mineral resource which is a result of successful drilling and model upgrading of a significant portion of the inferred resource to measured and indicated. Average grades are 0.40% copper and 0.012% molybdenum for an inferred resource of 1.1billion lbs of copper and 35 million lbs of molybdenum. "This increase represents the success we have achieved from our drilling program over the last year," said Gil Clausen, Augusta's President and CEO. "We expect this larger resource to positively contribute to the feasibility study update that is expected to be released shortly."