The Expo 4-6 occurrence is located the north side of the pass separating Bouleau Creek to the east and the headwaters of the Salmon River to the west, approximately 1.3 kilometres north of Little Bouleau Lake and 30 kilometres west of Vernon.

Regionally the area is underlain by volcanics, mudstone, siltstone, shale and fine clastic sedimentary rocks of the Devonian to Triassic Harper Ranch and(?) Nicola groups, which are intruded by Middle Jurassic granitic rocks. Volcanic rocks of the Eocene Penticton and Kamloops groups overlie the older units.

Locally, along a fault(?) escarpment, several interflow volcaniclastic sediments of the Kamloops Group host agate, jasper and silver mineralization. The silver mineralization is associated with chalcedonic quartz veins.

In 1988, a sample (53775) assayed 40.4 grams per tonne silver (Assessment Report 17882). Three other samples (53767 to 53769) taken that same year yielded from 24.3 to 41.7 grams per tonne silver (Assessment Report 17883).

During 1987 through 1989, Pacific Northwest Resources Inc. completed programs of prospecting; rock, soil and silt sampling and a 14.8 line-kilometre ground electromagnetic (VLF) survey on the area as the Expo 4 and 6 claims.

In 2006 and 2007, Okana Ventures Inc. completed programs of prospecting; rock, silt and soil sampling and a 14.0 line-kilometre ground electromagnetic (VLF) survey on the area as the Westmoreland claims.

In 2017 and 2018, Opal Resources Canada Inc. conducted programs of prospecting, geological mapping, geochemical sampling and trenching on the area as the Klinker/Ewer property.