The CU prospect is situated on a steep slope on the west side of the Ashnola River Valley, approximately 1.3 kilometres south of McBride Creek and 34 kilometres southwest of Hedley.
The area west of the Ashnola River, in the vicinity of McBride Creek, is underlain by Middle to Late Cretaceous felsic intrusions that may be subvolcanic equivalents of the Spences Bridge Group. These intrusions are in turn cut by small stocks and dykes of quartz porphyry and quartz diorite to quartz monzonite in the vicinity of McBride Creek. The various intrusives are cut by dacite and andesite dykes.
The occurrence is hosted in a quartz-feldspar-mica porphyritic rhyolite, exhibiting an aphanitic white to purple to dark-grey matrix. The unit is overlain to the south by a dark-grey feldspar amphibole porphyritic andesite. The rhyolite is cut by a breccia pipe (diatreme) containing angular to subangular fragments of rhyolite up to several metres in diameter in a matrix of limonite and fine rock fragments. The diatreme outcrops over an elliptical area trending north for 150 metres and up to 90 metres wide.
This breccia is one of three diatremes occurring along a broad northeasterly oriented arc. The two others are situated 2.2 kilometres (IT, MINFILE 092HSE153) and 3.4 kilometres southwest of this occurrence.
Hydrothermal alteration is intensive, but confined to the occurrence. Rhyolite fragments within the breccia pipe are strongly argillically altered, while the rhyolite country rock is fractured but unaltered. The limonitic and porous nature of the breccia indicates that extensive oxidation and leaching of sulphides has occurred. Voids between breccia fragments are often lined with drusy quartz in addition to limonite.
Mineralization comprises secondary copper minerals with traces of primary (hypogene) sulphides occurring interstitially to the breccia fragments. These minerals include malachite, chalcocite, cuprite, native copper and minor remnant pyrite and chalcopyrite. Diamond drilling to vertical depths of 100 metres indicates these minerals also occur in fractures in the rhyolite wallrock. A chip sample taken over 15 metres of strongly malachite-stained breccia assayed 0.19 per cent copper (Assessment Report 4377, page 11). One angled drillhole averaged 0.15 per cent copper over 135 metres (Assessment Report 17716, page 14, hole 79-1, 5-140 metres). Resampling of drillcore suggests higher gold values (up to 1.2 grams per tonne) are associated with intense argillic alteration and not with higher copper grades. A negative association between silver and copper is also evident. One resampled section analysed 0.68 gram per tonne gold, 5.8 grams per tonne silver and 0.10 per cent copper over 6.1 metres (Assessment Report 17716, page 15, hole 79-1, 67.1-73.2 metres). A second sample of core assayed 0.39 gram per tonne gold, 1.5 grams per tonne silver and 0.16 per cent copper over 9.8 metres (Property File - M. Renning, 1987, assay certificate, hole 79-1, 31.7-41.5 metres).
This deposit was first explored by Mineral Mountain Mining Company in 1972 as the No. 2 breccia zone. Ashnola Mining Company Ltd. carried out geological mapping, geophysical surveying, soil sampling and 586 metres of diamond drilling in three holes during 1979. Between 1960 and 1979, extensive work, including diamond drilling, geochemical and geophysical surveying, mapping and trenching, was carried out on the Ash (MINFILE 092HSE094) showing to the immediate north of the CU prospect. The deposit was reassessed by Murtec Resources Ltd. as part of the Lucky and Bill claims in 1987 and 1988 for precious metals in addition to copper. Work included resampling of the Ashnola Mining drillcore. The Lucky and Bill claims were later acquired by Messrs. Renning and Baldys. In early May 1990, a core splitter was packed up to the core shack and M. Renning sorted the complete set of core boxes for DDH 79-1 and DDH 79-2, then quartered 102 feet of core from DDH 79-1. The entire group of 21 samples were sent to Placer Dome in Kamloops where they were subsequently assayed by Eco-Tech Laboratories Ltd. Extremely anomalous gold and appreciable amounts of copper were reported from all of the samples.
Norman L. Tribe staked 32 claims over the Ash (MINFILE 092HSE094), CU and Cool Creek (MINFILE 092HSE190) showings in July 2003. Between 2004 and 2007, Tribe completed outcrop mapping over a 6 kilometre traverse. In 2011, Tribe optioned the property to Charlotte Resources Ltd. Later that year, Rich River Exploration Ltd. conducted a field exploration program consisting of prospecting and rock, soil and silt sampling.
