The Pluto occurrence is located approximately 8 kilometres east of the Sustut River and 5 kilometres south of Willow Creek (Assessment Report 4564). The similar Park 2 occurrence (094D 052), is located about 2 kilometres to the southeast.
The showing lies within sheared Lower Jurassic Telkwa Formation (Hazelton Group) volcanics. The dominant rock types are fine- grained andesitic tuffs and agglomerates. The major shears in the area trend northwest.
Disseminated chalcocite, bornite and chalcopyrite occur within malachite-stained shear zones. Occasionally, these sulphides form massively in small cracks and veinlets. The shear zones, up to 0.9 metres wide, range from 7 to 10 metres in traceable length.
The Pluto showing consists of a 2- to 3-metre-wide malachite- stained, east-west trending shear zone. A grab sample assayed 2.8 per cent copper and 78.8 grams per tonne silver (Assessment Report 21856).
In 1991, a 9-metre-wide quartz-calcite stockwork was discovered in outcrop near the Pluto showing. A grab sample, of a calcite vein mineralized with chalcocite and galena, from this stockwork in andesite tuff, assayed 1.38 per cent copper and 66 grams per tonne silver (Assessment Report 21856).
These stockworks are common in the claim area, but most of the sample values reflected only background values.
WORK HISTORY
An exploration programs completed by Rio Tinto in 1973 located fairly widespread copper mineralization as minor disseminations within calcite and quartz fracture-fillings and in minor shear zones on the property (Assessment Report 4855). A detailed sampling and mapping program, supported by trenching and diamond drilling, led to the conclusion that the copper mineralization was located in large fractures cutting across the volcanic units. Falconbridge had done some exploration on the same ground covered by the Rio Tinto claims during the summers of 1971 and 1972. The program lasted from June to August 1973. A total of 2498 geochemical samples were taken, mostly soil. The greatest emphasis was on geochemistry, due to the inaccessibility of outcrop. The last two weeks were spent mainly prospecting and mapping. Soil sampling was done at 60 metre spacings along contour lines with 150 metre vertical separation, and paralleling major streams. Two drill holes were completed on the Main zone of claim 'A 462', MINFILE occurrence A462 (094D 102).
In 1973, Wesfrob Mines Limited completed a soil geochemical survey on their Pluto claims (094D 075). 97 soil samples were collected. Copper mineralization occurring in 3-foot-wide shear zones was located. Disseminated chalcocite, bornite, and chalcopyrite and rarely lenses of massive sulphides were observed.
In 1974, a combined magnetic and electromagnetic survey 640 kilometres in total length was completed on behalf of Rio Tinto (Assessment Report 4921). Several high conductivity anomalies were recommended for follow-up. The Rio Tinto survey encompassed the following MINFILE showing areas: TJ (094D 050), Park 2 (094D 052), East Ridge (094D 053), Pond (094D 054), Red Copper (094D 055), Eight (094D 074), Pluto (094D 075), Tie (094D 089), A462 (094D 102).
In late September 1990, the Park 1 to 3 mineral claims were staked by Skeena Resources Limited, and an initial reconnaissance prospecting program was completed on the property. These claims covered Park 2 (094D 052), Pluto (094D 075) and A462 (094D 102) The programs consisted of twelve man-days on the property by three geologists and two prospectors between September 30, 1990, and August 1, 1991 on behalf of Skeena Resources Limited and Beauchamps Exploration. All known mineralized occurrences and showings in the area were geochemically sampled; sediment samples were collected from all streams within and adjacent to the claims; and rock sampling, reconnaissance prospecting, and geological mapping were completed (Assessment Report 21856). A total of 46 rock and 17 silt samples were collected. A photogeologic interpretation of the area was also completed.
