The Num IV (North Ridge) occurrence is located on the southwestern side of a mountain ridge situated west of the Taseko River and approximately 3 kilometres northwest of the northern end of Taseko Lake, at an elevation of approximately 2250 metres.
Regionally, the area is underlain by undivided volcanic rocks of the Upper Cretaceous Powell Creek Formation and undivided sedimentary rocks of the Lower to Upper Cretaceous Taylor Creek Group to the northeast.
Locally, northeast-striking limonitic shear zones with oxidized quartz-carbonate stringers are hosted by chlorite-altered andesitic flow breccias and feldspar crystal tuffs of the Upper Cretaceous Powell Creek Formation that have been intruded by a series of diorite dikes 7 to 30 metres wide. The volcanics strike northerly with a shallow dip to the west, whereas the dikes have a northwest trend and dip steeply from 75 degrees southeast to 80 degrees northwest.
In 1987, sampling of a roadcut (No. 8) yielded up to 1.68 grams per tonne gold over 1.5 metres (Sample 2241; Assessment Report 16873).
The area has been explored in conjunction with the nearby Vic (MINFILE 092O 027) occurrence since the early 1930s. During 1974 through 1976, Nemco Explorations completed programs of geological mapping, surveying, sampling, six diamond drill holes and road construction. In 1980, the area was staked by M. Boe and a program of blasting, trenching and sampling was performed near the summit. In 1983 and 1984, Sunmark Mines Ltd. completed programs of geological mapping and four underground diamond drill holes, totalling 244.0 metres, from the Lower adit. During 1985 through 1988, Stryker Resources Ltd. and Kingsvale Resources Ltd. completed programs of geological mapping, geochemical (silt, rock and soil) sampling, ground geophysical (magnetometer and VLF) surveying, extensive trenching and 5.9 kilometres of road construction. In 1992, Hemlo Gold Mines completed a program of soil sampling on the Num claims.
