The Orpiment zone forms a north trending zone 500 metres long and 300 metres wide with alteration exposed for 270 metres in elevation. The zone is predominately hosted by andesitic volcanic breccias and tuffs of the Hazelton Group. Early Jurassic intrusive rocks are exposed along the margins of the zone.

The Orpiment zone is characterized by intensely deformed quartz and pyrite, kaolinite, pyrophyllite and alunite altered rock with a pervasive north-northwest striking foliation. A coarse-grained orpiment vein within quartz, pyrite and alunite altered rock strikes north, cutting the foliation at a shallow angle.

The zone is weakly mineralized with gold. Elevated gold mineralization was identified on the eastern margin of the zone where strongly sheared carbonaceous siltstone containing discrete lenses of coarse-grained pyrite-quartz mineralization parallel to the foliation assayed 3.0 grams per tonne gold over gold over 1 metre (Assessment Report 23686). Elevated gold mineralization is also contained within small pods of semi-massive fine-grained pyrite within quartz, alunite, pyrite, kaolinite and pyrophyllite alteration. Yellow to pale green quartz veins hosting stibnite is strongly anomalous in gold. Pyritic silicification with yellow quartz veining is elevated in gold and highly anomalous in mercury.

It is reported that trench sampling occurred in 1992 and 1993 on the Orpiment zone. In 1994, mapping and 1 diamond drill hole totaling 231.5 metres occurred on the southern part of the zone. Gold values in the hole averaged between 1 and 0.3 gram per tonne gold (Assessment Report 23686). Mapping on the zone also occurred in 2003.

In the summer of 2011 Seabridge commissioned Quantec Geoscience to complete a magneto-telluric survey along its proposed tunnel route for engineering purposes. American Creek authorized the survey as the survey would also detect potential alteration zones/mineralization to depth. The results show several resistivity lows. One significant low is located some 1250 metres below the Orpiment zone extending for over 3 kilometres in length. This low appears to lie in the footwall of the Sulphurets Thrust fault and could mark a porphyry copper-gold deposit at depth.

In the summer of 2011 Seabridge commissioned Quantec Geoscience to complete a magneto-telluric survey along its proposed tunnel route for engineering purposes. American Creek authorized the survey as the survey would also detect potential alteration zones/mineralization to depth. The results show several resistivity lows. One significant low is located some 1250 metres below the Orpiment zone extending for over 3 kilometres in length. This low appears to lie in the footwall of the Sulphurets Thrust fault and was conjectured to mark a porphyry copper-gold deposit at depth.

See Eureka (MINFILE 104B 078) and Copper Belle (104B 518) for details of the Treaty property work history and more complete bibliography.