The Steamboat Mountain occurrence is located on the west side of Fourth of July Creek, opposite Volcanic Creek, approximately 23 kilometres north-northeast of Atlin.

The showing is hosted well within the Middle Jurassic Fourth of July Creek batholith (Three Sisters Plutonic Suite). In an area near the Husselbee (104N 001) showing, which is located 20 kilometres west-southwest, the batholith has been dated at 171 +/- 5 million years (Fieldwork 1990). Around Steamboat Mountain, the rocks are composed of vari-textured quartz monzonite which can be fine to coarse-grained and equigranular to an even coarser grained, more porphyritic phase. Orthoclase commonly makes up 40 per cent of the rock. This batholith has intruded primarily by Mississippian to Triassic rocks of the Cache Creek Complex in the Atlin area.

Mineralization consists of coarse blebs and rosettes of molybdenite which occur within vugs of milky white quartz veins. The veins often occur in sheeted fracture sets. Pyrite is common but no other sulphide minerals are documented. The veins/fractures have three distinct orientations with the most abundant striking 070 degrees and dipping 62 degrees to the northwest and striking 100 degrees and dipping 38 degrees to the northwest. Assays of mineralized zones are reported to vary from 0.2 to 1.5 per cent molybdenite (Assessment Report 2809). This occurrence is very similar to the mineralization of the Canyon zone (104N 058), which is located 6.7 kilometres southeast.

In 1968, the showing on Steamboat Mountain was originally staked by E. Mueller as the Bighill and Steephill claims. In 1970, the property was optioned to Buffalo Lake Mines and a preliminary topographic, geologic, and geochemical program was completed. The ground was restaked as the CC claim group by Canadian Johns-Manville in February 1972, but there is no indication that any work was done.

In 1980, the Bob 1 claim was staked for Placer Development Limited who conducted a short geochemical, geological, and geophysical program over the plateau portion of the claim, which includes the main zone of known molybdenum mineralization. A compass and chain grid consisting of seven north-south lines spaced 100 metres apart was constructed over the south end of the Steamboat Mountain ridge top and 183 samples were collected and sent for analysis. The 9.0-kilometre grid was also used to conduct magnetometer and VLF surveys.