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).
Prospecting in 2014, at the Go (Pyrrhotite Creek) main showing revealed chalcopyrite as veins, veinlets, blebs and fine-grained disseminations within and close to potassium feldspar and quartz-magnetite dikelets and veins. Hosts are dark green fine grained massive andesitic volcaniclastic rocks intruded by dioritic to granodioritic stocks and thin plagioclase and augite porphyry dikes. Mineralization appears to be concentrated along NW trending steep dipping panels or corridors that can be traced northwest up the slopes of Mt. Kaketsa.
The objective of the Pyrrhotite Creek drilling in 2014 was to test copper-gold-silver soil geochemical anomalies adjacent to an IP chargeability high, defined in 2013 geochemical and historic geophysical surveys. Mineralization follows NW striking panels or corridors, which dip steeply. The drilling intersected minor intervals of copper mineralization. Drilling intersected intrusive rocks ranging from syenite to granodiorite. Alteration assemblages include potassic, propylitic and chlorite-sericite plus/minus clay. Sericitic alteration is notably absent. Mineralization is sparse and dominantly vein controlled. Chalcopyrite is blebby within rare quartz veins, as 4 millimetres to 2 by 8 centimetre blebs in K-feldspar veins and syenite dikes. Quartz monzodiorite dikes contain up to 5 per cent blebby chalcopyrite. Intergrown chalcopyrite and pyrite blebs occur in epidote veins. Chalcopyrite blebs up to 1 centimete occur within 1 centimetre calcite-hematite-chlorite-epidote veins. Blebby chalcopyrite and pyrite occur in quartz-epidote-chlorite-magnetite-hematite veins and are strongly associated with chlorite. Apart from the narrow discrete zones mineralization is absent or occurs as a trace of very fine grained disseminated sulphides. Copper oxide mineralization is weak with neotocite-tenorite being the dominant copper oxide occurring on fractures to approximately 70 metres. Traces of malachite were identified and are associated with chalcopyrite in quartz veins. Veining is dominated by K-feldspar and epidote veins. Sulphide bearing quartz veins are rare. Sulphide barren quartz veins are also rare and occur sporadically at depth. Magnetite veins are locally intense and occur as 1 millimetre stringers to 10 centimetre veins occupying up to 30 per cent of the rock. One 8 metre interval (96-104 metres) assayed 0.28 per cent, 0.11 gram per tonne gold and 0.44 gram per tonne silver (Assessment Report 35362).
Prospecting about 1 kilometre to the east occurred in Polar Canyon mineralized area. Here chalcopyrite is less abundant and is seen as veinlets, blebs, and fine grain disseminations. Copper sulfide and oxide mineralization is noted to be concentrated in northwest-trending steeply dipping structures containing quartz-magnetite-pyrite and are generally proximal to intrusive. In contrast to the Go prospect, potassium feldspar vein and dikelet hosted chalcopyrite is much less abundant. Mineralization in general is lesser in abundance and occurrence when compared to the Main showing resulting in the broad diffuse soil anomaly along Polar Creek.
The area has been historically explored in conjunction with the nearby Copper Creek (MINFILE 104J 005) and Dick Creek (MINFILE 104J 035) occurrence and a complete regional and property exploration history can be found there.
In 1971 and 1972, Skyline Explorations completed five trenches, totalling 157.5 metres, and nine diamond drill holes, totalling 1097 metres, on the Pyrrhotite Creek occurrence. Drilling yielded intercepts of up to 0.32 per cent weighted copper over 14.4 metres in hole no. 8 (Caron, L. (2013-07-16): National Instrument 43-101 Technical Report on the Sheslay Property).
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.
In 2010 and 2011, Firesteel Resources Inc. completed programs of prospecting and rock sampling on the area as the Sheslay property.
In 2013, the property was optioned to Prosper Gold Corp. Soil geochemical surveys were completed over the Star (formerly Dick Creek) and Copper Creek target areas. Re-logging of all historic core was completed. Prosper completed 2339.77metres of diamond drilling in six holes (all on the Star), a 1462 line-km multi-parameter airborne geophysical survey on the entire Star property, a 30.4 line-km induced polarization and resistivity survey over the Star and Copper Creek targets. Two soil geochemical surveys programs were conducted, one consisting of 2554 soil samples (100 metre line spacing) covering the Star, Start East, Star North, and Copper Creek target areas, covering approximately 7.0 kilometres by 3.0 kilometers; and a 979 sample soil geochemical survey over the Pyrrhotite Creek occurrence at 50 metres intervals along uncut 100 metre-spaced lines.
The 2013 soil geochemical program across the Hackett River valley on the Pyrrhotite Creek target confirmed anomalous copper and molybdenum values and defined a new zone of anomalous copper, gold, and silver within Polar Creek canyon.
Drilling on the The 2014 exploration program included 20 diamond drill holes totalling 6,661.5 metres completed on the Star target, 1 diamond drill hole drilled to a depth of 137 metres on the Star East target and 3 holes totalling 964 metres on the Pyrrhotite Creek target. Drilling occurred from two pads separated by approximately 200 metres along a northwest trend to test geophysical and geochemical anomalies. Drill holes ranged from 314 metres to 332 metres in depth. Mineralization follows NW striking panels or corridors, which dip steeply. Discrete zones of copper mineralization were intersected with no significant results to report. Drilling intersected intrusive rocks that range from syenite to granodiorite. In 2014, 26 person-days spent mapping and prospecting Pyrrhotite Creek and Kaketsa Mountain to verify historic showings, define drill hole targets, and enhance geologic knowledge.