Twenty Mile Creek is situated west of Germansen Lake and flows north into the Omineca River at a point 21 kilometres west of Germansen Landing. Placer operations were largely confined to a stretch of the creek approximately 14.5 kilometres upstream from this point.
The area is underlain by the Upper Triassic Plughat Mountain Formation of the Middle Triassic-Lower Jurassic Takla Group. The closest bedrock outcrops are of green porphyritic basaltic volcanic rocks with large augite phenocrysts and minor plagioclase. Minor wacke and argillite also occurs. Several north striking fault strands crosscut altered volcanics at Twenty Mile Lakes, 1.5 kilometres north of the occurrence locality. Lower Jurassic Takla volcanics of the Twin Creek Formation and intrusive rocks of the Late Triassic-Early Cretaceous Hogem Intrusive Complex outcrop 8 and 12 kilometres to west respectively.
The placer workings were reported to be on extensive gravel flats, where gold was found within a metre of the surface. Boulder clay around the many large boulders along the creek was found to contain coarse and flaky gold, which appeared to have been concentrated in postglacial time.
The earliest recorded activity in the area occurred in 1901, but it was not until 1948 that serious testing of the creek was undertaken. A 7.62-centimetre interval between 15.49 and 15.57 metres in hole 5, one of seven drilled that year, analysed 103 milligrams of gold (Property File - Overburden drill logs). Sporadic activity on the creek continued into the 1960s.
Production of 2084 grams of gold for the period 1941-45 is listed in Table XXVII of Bulletin 28. Presently, small placer workings occur continuously for 1 kilometre south of and 5 kilometres north of the road crossing. The source of the placer gold is unknown.