The Rainbow Creek occurrence is located on the Rain claims along a north-flowing tributary into Rainbow Creek, approximately 15 kilometres south of the Mount Milligan deposit (093N 194) and 152 kilometres north-northwest of Prince George.

The showing consists of up to 20 per cent pyrite in a grey and black fault zone breccia with quartz and carbonate veining. The fault zone cuts through augite porphyry agglomerates and white weathering tuffaceous black siltstone and mudstone of the Upper Triassic Witch Lake Formation (Takla Group). Gossanous zones contain 3 per cent disseminated pyrite with magnesite and traces of fuchsite. One of the veins analyzed 1.4 grams per tonne gold and 0.18 per cent arsenic (Fieldwork 1990, page 108).

A strong arsenic-antimony-zinc geochemical anomaly occurs at the creek confluence. Trace amounts of chalcopyrite were also observed in andesitic flows and breccias on the property.

The Rainbow property consists of two mineral claims located within the Mount Milligan property (093N 194) boundary. Previous exploration conducted on the property between 1988 and 1991 by BP Resources Canada Ltd. and Placer Dome Inc. included geological mapping, soil sampling, and airborne magnetic and ground induced polarization (IP) geophysics. The Rainbow property went dormant when the Mount Milligan project was put on hold shortly afterward.

Exploration was reactivated in 2008 when Terrane Metals Corporation completed a 1458 line-kilometre airborne magnetic-electromagnetic (HeliGeotem) survey over the Mount Milligan and Rainbow properties to target satellite deposits associated with the Mount Milligan porphyry system. Terrane Metals conducted stream sediment sampling using the bulk leach extractable gold technique, which identified copper and gold stream sediment anomalies that drain the Rainbow property (www.bcgoldcorp.com).

In 2009, BCGold Corp. completed a short exploration program consisting of six stream sediment samples, 32 soil samples, and 20 prospecting samples.

In 2012, BCGold Corp. conducted a mobile metal ion (MMI) sampling program on the Rainbow property. Results showed a strong copper-gold soil anomaly that measures approximately 350 by 250 metres and is open to expansion in all directions. The anomaly returned a strong gold response, with values up to 56 times background values, and is associated with a stream sediment anomaly that drains a 350 by 700 metre topographic high with no outcrop exposure (Press Release - BCGold Corp., January 17, 2013).