During 2012, an initial resource estimate was released for the Bermingham exploration project, which is in the area of the historical Bermingham mine, totaling nearly 4 million ounces of silver in the Indicated resource category and more than 1 million ounces of silver in the Inferred resource category. Seventeen drill holes comprising both infill and extension drilling were completed into the Bermingham target during the year for an approximate total of 6,000 meters of drilling. Silver mineralization is now known to extend at least 500 meters along strike and 400 meters down dip in the Bermingham area, and remains open. Review and update of the Bermingham resource is ongoing.
The Bermingham resource model comprises three veins, of which two have been included in the resource estimate (the Bermingham Vein and Bermingham Footwall Vein). All three veins occur in the hangingwall of the northwest trending post-mineral Mastiff Fault (termed the Etta zone), exposed in the larger of the historical Bermingham open pits. Alexco conducted surface diamond drilling programs at Bermingham between 2009 and 2011, with twenty-three holes drilled in the Etta zone totaling 6,442 meters. The drilling outlined the Bermingham Vein with a north-northeast strike and moderate southeast dip, converging to the northeast with the Bermingham Footwall Vein which has a northeast strike and dips moderately to steeply to the southeast. The Bermingham Vein and Bermingham Footwall Vein typically exist within a 5 to 10 meter wide structurally-damaged and complex zone containing discrete veins 0.5 to 2.5 meters wide, consisting predominantly of carbonate (dolomite, ankerite and siderite), quartz and calcite gangue with sulphides; sphalerite, galena, pyrite and arsenopyrite, and accessory chalcopyrite, argentian tetrahedrite, jamesonite, pyrargyrite and native silver.
The Bermingham resource was estimated using 3-D Gemcom block modeling software in multiple passes in 5 by 5 by 3 meter blocks by inverse distance squared. Grade estimates were based on capped one meter composited assay data. Capping levels were set to 2,500 grams per tonne for silver for the Bermingham Vein and 2,000 grams per tonne for the Bermingham Footwall Vein, and 0.25 grams per tonne gold for both the Bermingham Vein and the Bermingham Footwall Vein; and lead and zinc were both capped at 10% for both the Bermingham Vein and the Bermingham Footwall Vein. Blocks were classified as indicated mineral resources if at least two drill holes and four composites were found within a 40 by 40 meter search ellipse for Bermingham Vein and a 40 by 60 meter search ellipse for Bermingham Footwall Vein. All other interpolated blocks were classified as inferred mineral resources.