T.38N. R.19E. and sec. Pyrrhotite is a major sulfide mineral at the Duval massive sulfide deposit, sec. 2 and 3 T.35N. R.18E. and sec. Here it occurs intergrown with pyrite, sphalerite and chalcopyrite in a magnetite-grunerite iron formation. The pyrrhotite is bronzy, iredescent and strongly magnetic.
Analyses show it to be devoid of any nickle minerals.
Prospects were dug in a vein which was traced 8 feet below the surface, where it openned into a zone 41 feet wide. The basal member consists of metamorphosed massive lava flows and volcanoclastic sediments. The middle member is mostly metamorphosed sandstones. It is particularly common in the footwall stockwork zone where it is associated with chalcopyrite, pyrite and magnetite. Significant pyrrhotite occurs in sec.