The (East) Twin Creek occurrence is located on the eastern fork of Twin Creek, approximately 3.5 kilometres south east of its junction with the Tchaikazan River.
The area is underlain by volcanic tuffs and argillaceous sediments of the Lower Cretaceous Taylor Creek Group and Tchaikazan River succession. A lobe of granodiorite of the Jurassic to Tertiary Coast Plutonic Complex forms the south western head of the valley, approximately 500 metres from the mineralization.
Locally, a series of intensely silicified fracture zones, one of which carries considerable realgar mineralization, occur on the banks of a creek in a broad, drift-covered valley that drains northward into the Tchaikazan River. Distinct, orange- weathering zones of rubble and outcrop occur 35 metres apart on either side of the creek, and a third isolated zone is exposed 150 metres further upstream. Quartz-carbonate veining occurs within areas of quartz-ankerite and siderite-kaolinite alteration. Vein breccias contain moderately silicified volcanic fragments as well as banded chalcedonic vein material indicating multiple episodes of brecciation and siliceous healing. Cavities lined with quartz and carbonate crystals are common. Realgar, orpiment, arsenopyrite with traces of cinnabar and chalcopyrite occur as fine disseminations, in veinlets, and as crust on fracture planes in one zone approximately 4.5 metres in true width.
Assays of two channel samples across this zone graded an average of 0.2 per cent arsenic and selected samples contain up to 0.4 per cent arsenic; antimony values range from 0.007 to 0.011 per cent (Bulletin 81). Precious and base metal values are low in the zone of visible mineralization; however, 0.1 to 0.2 grams per tonne gold is present in samples taken from the other alteration zones.
In 2007, several samples from the showing assayed greater than 0.3 per cent arsenic, 0.5 per cent copper, 1 per cent lead and zinc (Assessment Report 31141).
In 1980, Du Pont completed a program of geochemical sampling and prospecting on the area immediately to the south east as the Bee and Fall claims. In 1988, New Global Resources completed a program of geochemical sampling and geological mapping on the area as the Zan claims. In 1998, Pellaire Gold Mines completed a program of geological mapping and rock, silt and soil sampling on the area. During 2005 through 2012, Valor Resources completed programs of silt, soil and rock sampling, geological mapping, ground magnetic and electromagnetic surveys and airborne geophysical survey on the area.