On the northern flank of the hill, massive sulfide extends more than 270 m from north to south and more than 100 m from east to west, but the western edge of the deposit has not been defined with certainty. Within this area there is nearly continuous outcrop of massive sulfide. All of the active hydrothermal vents occur in an area with abundant sulfide mounds along the northwestern flank of the hill. Sulfide samples collected at the surface of the deposit are dominantly pyrrhotite with variable amounts of isocubanite and chalcopyrite and minor sphalerite, galena, lollingite, arsenopyrite, and boulangerite. Sulfate occurs as barite crusts and chimneys on massive sulfide and intergrown barite-anhydrite in active vents.
Precious metals are significantly enriched relative to Middle Valley massive sulfide.