The Oro 4 area is regionally mapped as being underlain by undivided arc volcanic and marine sedimentary rocks of the Upper Triassic Stuhini Group. Pennsylvanian tuffs and sediments and massive amygdaloidal basalts of the Stikine Assemblage are regionally mapped within about 1.5 kilometres to the east-northeast. A north-northeast trending fault separates the Stuhini and Stikine Assemblage rock from Middle to Upper Triassic foliated quartz diorite, to the east.

Quartz-carbonated veins cut the rocks and shear zones weather to orange-brown gossans. A sample of pyritized tuff, adjacent to a shear zone with hematite, assayed 2.26 grams per tonne gold (Assessment Report 13251). Assay values of 27 other samples were not significant.

Work History

In 1983, L. Majcen acquired the Oro 4 claim by staking. The 1984 program on the Oro 4 claim was conducted by H.E. Kucera consisted of prospecting, sampling, and geological mapping of the claim block. A total of twenty-eight rock samples were collected and assayed for gold and copper. Rock samples were taken of the volcanic-sedimentary package in areas of gossans and/or alteration. Two stream sediment samples were taken and assayed for gold, silver, copper, antimony, and arsenic. At this time, Placer Development Ltd. did a traverse over Oro 4 and their sample results confirmed a weak gold anomaly in the vicinity designated of Station 15, near the northeast corner of the Oro 4 claim where the high gold sample was taken.

In 1992, a BC Geological Survey geological mapping project in the Tatsamenie and Bearskin lakes area resulted in an updated regional geological framework and the discovery of several new showings including DB (104K 121), Ro (104K 123) and Jon (104K 124). The Ro is located about 800 metres north-northeast of the Oro 4 occurrence.

In 2019, Brixton Metals Corporation expanded their Thorn property through staking and acquisition of claims including those covering all the Highliner (104K 099), Oro 4 (104K 100), DB (104K 121), Ro (104K 123) and Jon (104K 124) showings. No further work was reported on the Oro since the initial work in 1983. Refer to Thorn (104K 031), Chivas (104K 180), East Outlaw (104K 083), Oban (104K 168), Trapper (Inlaw) (104K 078) and Metla (104K 161) for details of the work history of the greater Thorn property.

In 2020, Brixton Metals Corporation completed a program of geochemical (rock and soil) sampling, a 12.5 line-kilometre ground induced polarization survey, a 715 line-kilometre airborne magnetic and electromagnetic survey and 19 diamond drill holes, totalling 5292 metres, on the area of as part of the Thorn property. Drilling was performed on the Outlaw (MINFILE 104K 176) occurrence area.

Refer to nearby discovery Ro (104K 123) and Golden Bear (104K 079) for related information on area geology and work history.