The Grace showing is located east of the headwaters of the South Unuk River, west of Mount Pearson.
The mineralized area is underlain by Jurassic age folded metavolcanic and metasedimentary rock that may be correlative to the Lower Jurassic Unuk River Formation, Hazelton Group. The predominant rock types are metasediments consisting of quartz-biotite and quartz-biotite-chlorite phyllonites and schists with minor interbedded limestone and graphitic schists. The original rocks are considered to be greywacke, marl and sandstone. The metamorphic rocks have been intruded by small subcordant bodies of diorite, leucodiorite and/or syenite and hornblende diorite of Triassic-Jurassic age. A north trending stock diorite, several kilometres in length, occurs adjacent to the west of this area and a smaller syenitic stock exists to the immediate east. Lower Jurassic Stuhini Group rock is predominant to the immediate west.
Volcanic rocks of the Unuk River Formation are exposed east and west of the area of interest. These consist of pillowed andesitic rock to the west and andesite to the west. These grade into greenstone, schists and phyllonite. Grove (Bulletin 63) has also mapped a small area of Middle Jurassic Salmon River Formation rock (Hazelton Group) overlying the metamorphics. He has also defined a northwest trending cataclasite zone, developed within Lower Jurassic rock, occurring along the path of the South Unuk River. The occurrence is hosted within this zone or occurs just east of it.
The major structural features are two major subparallel north trending steeply dipping faults. One, the "Granduc fault", cuts diagonally across the claim group. The second major fault lies about 1.5 kilometres east of the "Granduc fault". Cross fracturing and shearing is a prominent feature in the block bounded by these faults. Mineralization is related to these structures.
Mineralization consists of widely seperated lenses of magnetite and/or chalcopyrite that occurs in the cross fractures and shears. The largest lens measures 30 by 0.8 metres. Locally irregular and widely spaced carbonatized zones in the chlorite and biotite schist contain disseminated chalcopyrite and magnetite. These are small, widely seperated, and show no continuity. Abundant finely disseminated pyrite with sporadic specks of chalcopyrite occurs in schist or phyllonite along the Granduc fault zone (Assessment Report 484).
Chalcopyrite mineralization is reported to occur in volcanics and syenite at several localities east of the occurrence area (National Mineral Inventory #104B8 Cu4).
In 1962, London Pride Silver Mines Ltd conducted prospecting and mapping on their North Group consisting the Grace and Sigrun claims (Assessment Report 484).
In 1990, parts of the North Group were held as the GC2 and Pearson claims by Amphora Resources, who conducted an 87.5 km airborne magnetic and electromagnetic survey (Assessment Report 19995). However, the mineralized area of the Grace showings appears to be just south and/or east of the surveyed area.
