The GO occurrence is located on the east slopes of Kaketsa Mountain, about 2 kilometres west of Pyrrhotite Creek, approximately 52 kilometres northwest of the community of Telegraph Creek.
A number of copper showings are evident near the contact of the Late Triassic Kaketsa pluton with Upper Triassic Stuhini Group volcanic and related sedimentary rocks. The main area of interest is within a 1828 by 762 metre zone of weakly pyritic rocks along the eastern margin of the pluton. Here, copper mineralization is localized along northwesterly trending fractures in a large embayment in the pluton. Pyrite and traces of disseminated chalcopyrite are also found in many of the dikes and irregular intrusive bodies to the east and southeast of the main contact.
The volcanic rocks are mainly porphyritic flows with lesser tuffs and tuffaceous siltstones. The flow rocks form massive units without any discernible stratification; they are grey to dark green andesitic to basaltic porphyries with euhedral, prismatic phenocrysts of amphibole and uralitic hornblende up to 1 centimetre diameter. Tuffaceous rocks occur in a single unit about 60 metres thick and outcrops as a persistent north-northeast to northeast striking band with 60 to 75 degree dips to the west. The Kaketsa pluton is an elliptical intrusion 4 by 5.6 kilometres in diameter. Hornblende gave a K-Ar date of 218 +/- 8 million years (Geology, Exploration and Mining in British Columbia 1972, page 548). The intrusion has been forcefully emplaced as it is foliated and contains many xenoliths near its border ranging in size from pebbles to large blocks. The pluton and related dikes in the area of mineralization are mainly medium grained hornblende diorite. The core of the pluton is medium to coarse grained, equigranular quartz diorite or granodiorite.
Minor intrusions related to the Kaketsa pluton intrude volcanic rocks to the east and southeast of the main pluton. They form dikes and irregular masses separated by screens and small roof pendants of volcanic rocks. Two other groups of dikes are recognized: an early suite related to the volcanic rocks and a later suite of monzonite and syenite intrusions that may be late differentiates of the main diorite body. The early dikes are diorite to diabase in composition; the younger dike suite consists of diorite to quartz diorite and leucocratic grey and pink porphyritic dikes of monzonite and syenite.
Most commonly, alteration is seen as thin, widely spaced K-feldspar flooded fractures that also contain epidote and minor quartz, siderite, calcite and sulphides. Otherwise, alteration is generally weak and is indicated by a greenish colouration in the volcanic rocks caused by dispersed epidote, chlorite, actinolite and magnetite that occurs mostly along fractures. Fault and fracture zones that commonly contain thin bands of mylonite also contain stringers of quartz, sulphides, magnetite, hematite, siderite and calcite. A late-forming alteration consists of a soft buff to pink fibrous mineral that coats fracture surfaces in sheared rocks and was identified as the zeolite laumontite.
Sulphide mineralization is widespread as fracture-controlled pyrite in volcanic rocks and disseminated pyrite in diorite dikes. Chalcopyrite occurs in trace amounts with pyrite but higher copper grades are localized in steep, predominantly northwesterly striking fracture zones. In the area of the main showings, a series of subparallel or interconnected fracture and shear zones and thin bands of mylonite have localized mineralization in a 91 by 60 metre area. Chalcopyrite is seen as fracture fillings and fine grained replacements in the fractured volcanic rocks and margins of dikes within the zone. Chalcopyrite is frequently accompanied by patches, fracture fillings and stringers of specular hematite and magnetite. Along strike from the main zone to the northwest and in a number of other localities, mineralization is more vein-like in character with siliceous zones in the highly fractured rocks containing impregnations of fine-grained magnetite and patches or grains of chalcopyrite, pyrite, sphalerite, hematite, marmatitic magnetite, siderite and possibly marcasite.
A considerable amount of goethite, brochantite, chalcocite, possibly covellite, and films of undetermined black oxides were noted in trenches. Three samples of typical mineralization from the centre of the main zone totalling 13.7 metres yielded a mean value of 0.58 per cent total copper of which 0.34 per cent was oxide copper and 0.24 per cent was sulphide copper. The amount of copper enrichment due to deposition of secondary copper minerals is uncertain but may be equivalent to the amount leached (Geology, Exploration and Mining in British Columbia 1972, page 549). Chip samples taken from veins in 1989 analysed up to 1.35 grams per tonne gold (Assessment Report 18927).
In March 2002, the Copper Creek 1 and 2 claims were staked on behalf of D. Mehner, A. Travis and D. Barker. In February 2003, the Copper Creek claims were optioned to Firesteel Resources Inc. At the time of option three prospects were encompassed by the claims: Copper Creek (104J 005); Star (Dick Creek, DK) (104J 035); and GO (Pyrrhotite Creek) (104J 018). From 2003 to 2005, all work was directed to the DK zone (104K 035) and the reader is referred to that occurrence and the Copper Creek occurrence for further details of the Copper Creek property. In 2006, Garibaldi Resource Corp. completed a helicopter borne magnetic survey that covered the south-central part of the Grizzly property; survey coverage consisted of approximately 510.2 line kilometres including 49.3 kilometres of tie lines.