The Northwest Zone showing is located west of Sicintine River, approximately 4 kilometres south of its confluence with Tommy Jack Creek.

The area is situated near the eastern edge of the Bowser Basin, and is primarily underlain by fine- to medium-grained sediments and volcaniclastics of the Bowser Lake Group. Quartz diorite and fine-grained felsic dikes cut the sediments. The dikes typically intrude in swarms along fault zones, and are commonly pervasively altered to sericite or carbonate. Quartz and quartz-carbonate veins occur both in the sediments and in dikes and appear to be at least spatially associated with dikes or dike contacts, and with faults. Individual veins range up to 2.4 metres in width, but typically are less than 1 metre wide. They can occur as closely spaced sheeted vein systems or as stockwork zones, comprising up to 10 per cent of the rock.

Generally, sulphide content is typically less than 15 per cent, although massive sulphide veins are known. Sulphides consist of pyrite, galena, arsenopyrite, sphalerite, pyrrhotite, chalcopyrite and trace amounts of tetrahedrite and pyrargyrite. Gangue mineralogy is quartz or a mixture of quartz, calcite, dolomite and ankerite.

From 1984 through 1989, Noranda completed programs of geophysical, geological and geochemical surveys and 35 diamond drill holes over the area and the nearby Tommy Jack (094D 036) occurrence.

In 2002, Gold City Industries optioned the Gosico property and completed a program of prospecting, geological mapping, hand trenching and rock sampling.

During 2005 through 2009, Rox Gold Inc. completed programs of geochemical sampling, diamond drilling, mapping and prospecting on the area as the TJ Ridge property.

In 2005, hand trenches were dug to follow-up a multi-element soil anomaly. Trenching was successful in locating two quartz veins in outcrop. The first vein is a relatively narrow quartz vein, 5 to 12 centimetres thick, mineralized with pyrite, galena and sphalerite. Approximately 200 metres to the north east, a quartz vein, averaging 35 centimetres in width, is hosted within bleached siltstone and contains pyrite, galena and arsenopyrite. Sampling of the two veins has returned values up to 16.3 grams per tonne gold with 96 grams per tonne silver and 13.9 grams per tonne gold with 86 grams per tonne silver, respectively (Assessment Report 29087).

In 2007, a drilling yielded results of up to 0.98 gram per tonne gold, 9.3 grams per tonne silver, 0.34 per cent zinc and 0.21 per cent lead over 10.34 metres in hole ROX-07-05 and 3.02 grams per tonne gold over 2.00 metres in hole ROX-07-02 (Pinsent, R.H. (2010-02-10): Geology and Mineral Potential of the TJ Ridge (Tommy Jack Creek) Property).