The area of SU-688 is underlain by Lower Jurassic rocks of the Betty Creek Formation, Hazelton Group.

In 2016, Pretium Exploration targeted drill Hole SU-688 on a northeast trending, 70 centimetre wide quartz-carbonate vein breccia that was discovered while prospecting the previous year. A sample taken in 2015 graded 3,730 grams per tonne silver and 3.09 per cent copper 0.23 per cent lead , and 1.44 per cent zinc in a 70 centimetre chip sample (Assessment Report 36712). The vein breccia is hosted by an amygdaloidal basalt, underlain by dacitic volcanic rocks.

The top 60 metres of the Hole SU-688 were amygdaloidal basalt and from about 60 metres to 342 metres (EOH) the hole intersected intermediate volcanic rock (andesite, latite). At 63 metres depth, SU-688 intersected 0.85 metre grading 275 grams per tonne silver, 0.236 per cent copper, 0.028 per cent lead, and 0.068 per cent zinc (Assessment Report 36712). Silver-rich electrum was observed at 261.82 metres depth, grading 197 grams per tonne silver over 0.5 metre (Assessment Report 36712).

See Tippy Lake (104B 382) for a related work history.