On the Property, polymetallic volcanogenic massive sulfide (“VMS”) style deposits (including Arctic) and prospects are hosted in the Ambler Sequence, a group of Middle Devonian to Early Mississippian, metamorphosed, bimodal volcanic and volcaniclastic rocks with interlayered metasedimentary rocks. VMS-style mineralization is found along the entire 68-mile (110-kilometer) strike length of the district.
Mineralization at the Arctic deposit occurs as semi-massive to massive sulfide beds within primarily graphitic and quartz mica (+/- chlorite) schists. The sulfide beds average 13 feet (4 meters) in thickness but vary from less than 3.3 feet (1 meter) to as much as 59 feet (18 meters) in thickness. The bulk of the mineralization is within an area of roughly 0.4 mi2 (1 km2) with mineralization extending 820 feet (250 meters) below the surface. Mineralization is predominantly coarse-grained sulfides consisting mainly of chalcopyrite, sphalerite, galena, tetrahedrite, arsenopyrite, pyrite and pyrrhotite. Trace amounts of electrum and enargite are also present.