The Kopr showing is located at an old abandoned adit, at the headwaters of Loak Creek, 3.75 kilometres southeast of Apex Mountain and 9 kilometres north-northwest of Olalla, British Columbia.
The Kopr showing has been explored by Apex Exploration and Mining Co. Ltd. in 1979 and 1980 in the vicinity of an old adit. The adit probably dates back to the early 1900s.
The regional geology of the area consists of a series of Carboniferous to Triassic volcanic and sedimentary rocks that have been intruded by granitic Okanagan intrusions. Larger intrusions are composed of granite and granodiorite, while smaller stocks are composed of diorite and gabbro. Numerous sills, dikes and apophyses are associated. Carboniferous to Triassic rocks are assigned to the Shoemaker and Old Tom formations. These rocks form the eastern limb of a large anticlinal fold with fold axes striking roughly north. The Shoemaker consists of cherts, greenstone and minor argillite. The cherts of the Shoemaker Formation are commonly lighter coloured (buff, pink, grey, grey-green) and commonly show a saccharoidal texture. The overlying Upper Triassic Independence Formation consists of interbedded, dark grey to black chert (commonly rusty or red stained), chert breccia, and siliceous greenstone containing disseminated pyrite and pyrrhotite or pyrite and arsenopyrite.
Grey, medium-grained diorite with hornblende phenocrysts occurs in the fault zone at the Kopr showing. The diorite shows no shearing or fracturing and hosts coarse, disseminated pyrrhotite grains.
At the Kopr showing, the Shoemaker Formation is composed of dark grey, sillimanite hornfels. In thin section, this rock is composed of sillimanite-rich aggregates that enclose or are interbanded with quartz-feldspar masses. The sillimanite is associated with cordierite, orthoclase, uralite, quartz, hematite and a few grains of forsterite and some apatite. The sillimanite hornfels has been replaced by silica so that the present rock is composed of embayed and serrated inclusions of hornfels in a mosaic of anhedral secondary quartz. Pyrite commonly occurs as fracture fillings and chalcopyrite is scarce. Magnetite is locally present.
The Old Tom Formation consists of propylitically altered, dark grey to green, fine grained, massive greenstone (andesite?) with an amygdaloidal texture. In thin section the matrix consists of epidote, zoisite and fibrous amphibole with some minor quartz and albite. Amygdules are commonly composed of optically positive, non-fibrous zeolite. In places the matrix has been partially replaced by quartz. The greenstone carries pyrite and in places appreciable chalcopyrite. Magnetite is generally absent. White, fine grained, crystalline limestone with sporadic dark patches is locally present within the greenstone at the Kopr showing. Skarn is also associated with greenstone at the Papex (082ESW049) and Kopr showings. Brown garnet, calcite, quartz and akermanite with pyrite and chalcopyrite comprise skarn mineralization at the Papex showing.
At the Kopr showing pyrite and chalcopyrite occur in the footwall of a 12-metre wide fault, striking 260 degrees and dipping 75 degrees north. The hangingwall and footwall are hosted by hornfels of the Shoemaker Formation. An adit was driven 15 metres below the surface expression of the fault, on the footwall side. The hostrock is Shoemaker hornfels at the adit but dump material consists of skarn composed of garnet, calcite and quartz with pyrite and chalcopyrite.
Topper Gold Corp. and Grand National Resources Inc. drilled on the Nugget claims in 1998. See also Kero (082ESW209).
