The Marg-Sum occurrence is located on the north side of Hatchery Creek, approximately 300 metres west of the logging road bridge.

The area is underlain by the Permian Vedder Mountain metamorphic complex, which is described as a sequence of lower amphibolite- to kyanite- grade metamorphic rocks. Locally, they consist of a mixture of grey to green metamorphosed basalts, diorites and andesitic rocks. To the south, conglomerate and coarse clastic sedimentary rocks of the Upper Jurassic Kent Formation outcrop, while to the north undivided sedimentary rocks of the Devonian to Permian Chilliwack Group are exposed.

Locally, greenstones (serpentinite) host quartz veins with sericite alteration and sulphide mineralization, consisting of pyrite, pyrrhotite and lesser chalcopyrite. Pentlandite and chromite are also reported to occur in the silicified greenstones. In 1982, a sample (K-4-82) assayed 0.30 per cent nickel, 0.20 per cent chromium, 0.03 per cent cobalt and 0.02 per cent copper (Assessment Report 11133).

Also, at this time, another nearby outcrop of limestone and greenstone was sampled (K17/82) and yielded 7.7 grams per tonne silver, 0.16 per cent lead, 0.17 per cent zinc and 0.02 per cent copper (Assessment Report 11133).

In 1990, a sample, taken approximately 300 metres to the north, assayed 0.89 gram per tonne gold and 0.578 per cent copper (Assessment Report 21044).

During 1981 through 1988, the area was prospected and sampled as the Marg-Sum 1-3 claims. During 1988 through 1990, the area was prospected as the Mwito 1-2 and Cultus North claims. In 2004, the area was prospected as the KPH claims.