The Butterfly Creek occurrence is underlain by Pennsylvanian metavolcanic and metasedimentary rocks of the Stikine Assemblage. The Stikine rocks are in contact to the immediate west and south with Late Early Jurassic granodioritic intrusions of the Cone Mountain Plutonic Suite and granite intrusions of the Paleocene to Eocene Sloko-Hyder Plutonic Suite.

In 1990 Shellex Gold prospected the head of Butterfly Creek and collected 3 mineralized outcrop samples. Three mineralized float samples thought likely to have come from the cliffs above consisted of andesite, crystal tuff or skarned rock. They were mineralized with carbonate and/or quartz veins, chalcopyrite, pyrrhotite, garnet and/or epidote.

One of the outcrop samples (90G4R167) taken across 1 metre of andesite containing carbonate veinlets with up to 10 per cent pyrrhotite, pyrite and chalcopyrite assayed 0.77 per cent copper, 0.58 gram per tonne gold and 36.7 grams per tonne silver (Assessment Report 21148). A nearby altered mafic volcanic outcrop sample (90G4R168) hosted carbonate-quartz veins from 15 to 20 centimetres thick. One of the “float” samples (90F4R166) was described as crystal tuff with up to 10 per cent pyrrhotite, 3 per cent chalcopyrite and possible bornite assayed 0.26 per cent copper, 28.2 grams per tonne gold, 4.5 grams per tonne silver and 328 part per million bismuth (Assessment Report 21148).

In January of 1989, the RB 23, RB 24, RB 25 and RB 29 were staked and later grouped under the name Phacops. In 1990 Shellex Gold Corp conducted work consisted of prospecting, surface sampling and geological mapping. Stream sediment fines were collected from both running and dry stream channels. A contour soil line was run at 1675 metres on the flanks of Mount Phacops. A total of 37 rock, 81 soil and 17 silt samples were collected.

For related information see the MINFILE showing labelled Butterfly Lake, about 3 kilometres to the northeast the Butterfly Creek showing.