The Robertson (L.48G) occurrence is located on the Koksilah River, approximately 4.8 kilometres north west of Grant Lake.

The area is underlain by argillite, greywacke, chert and diabase dykes of the Mississippian to Pennsylvanian Fourth Lake Formation of the Buttle Lake Group. Overlying this are basaltic volcanics of the Upper Triassic Karmutsen Formation (Vancouver Group) which in turn are overlain mainly by rhyolitic to basaltic volcanics of the Lower Jurassic Bonanza Group. Contact between metamorphosed volcanics and dioritic gneiss of the Mesozoic to Paleozoic Wark Gneiss occurs close to the showing.

The Robertson showing occurs as lenses of skarn material in fissures in a shear zone within volcanic rock. The ore consists of galena, pyrite, sphalerite and minor amounts of molybdenite and chalcopyrite all in a quartz gangue mixed with breccia, garnetite and calcite.

One exposure occurs about 60 metres above the Koksilah River where a mineralized quartz vein, about 45 centimetres in width, strikes northeast and dips vertically. Another outcropping of ore occurs in the river bank, where a vein-like occurrence has been drifted on for about 9 metres. This exposure shows a quartz vein about 1 metre wide at the portal, also striking to the northeast but dipping 55 degrees to the southeast.

By 1917, approximately 75 metres of drifting had been completed on the Robertson Crown Grant. A sample taken from the dump at the portal assayed 0.69 grams per tonne gold, 206.71 grams per tonne silver and a trace of copper (Minister of Mines Annual Report 1917, page 270). In 1928, samples from the lowest of the dumps assayed 2.6 per cent lead, 7 per cent zinc and 13.7 grams per tonne silver (Assessment Report 18848).

In 1978, Union Miniere Expl. & Mining Corp. Ltd. Completed a program of soil geochemical sampling on the area as the Metal and Heavy Metal claims. In 1985, Imperial Metals Corp. completed a program of silt and stream sampling on the area as the Dunc 1-3 claims. This work identified anomalous gold in the north fork of the Koksilah River. In 1988, Abacom Resources completed a program of geochemical sampling, geological mapping and ground geophysical surveys on the area as the Bingo and Peso claims.

In 1991 and 1992, Boston Industries completed programs of geological mapping and a ground electromagnetic survey on the area as the Koksilah claims.