The Diddi occurrence is located on a west facing ridge above Raffuse Creek at an elevation of approximately 1245 metres, approximately 2.5 kilometres north of Clarion Lake.

The area is underlain by a roof pendant of rhyolitic and andesitic tuff and agglomerate of the Lower Cretaceous Gambier Group. The volcanic rocks overlie Late Jurassic leucocratic granodiorite of the Jurassic to Tertiary Coast Plutonic Complex. The elongate, keel shaped, roof pendant trends west-northwest for 2 kilometres and is up to 1 kilometre wide.

Locally, a green (chlorite?), altered rhyolite hosts chalcopyrite, sphalerite and malachite mineralization.

In 1981, a rock sample (No. 108) assayed 0.36 per cent copper and 2.25 per cent zinc (Assessment Report 09714).

During 1980 through 1982, Alpen Exploration completed programs of rock, soil and silt sampling, prospecting and a ground magnetometer survey on the area as the Diddi, Kathryn and Sarah claims. During 2005 through 2015, the area was prospected and sampled as the Mamquam 1-5 claims.