The Knob Hill occurrence is located on top of Mullins Hill, approximately 8 kilometres northeast of Carmi.
The area occurs in a contact zone between metasediments of the Carboniferous-Permian Anarchist Group and quartz diorite of an unnamed Middle Jurassic intrusion. This intrusion was previously mapped as part of the Middle Jurassic Nelson Intrusions (Geological Survey of Canada Map 1736A). The garnet present may be a result of high-grade metamorphism and not skarnification.
Mineralization consists of specks of chalcopyrite, molybdenite and pyrite in small lenses of garnet skarn and disseminated in hornfelsed contact zones associated with dikes. Mineralized areas are "capped" by a thick, hard layer of iron oxides.
In 1992, a rock sample (22214) assayed 0.535 per cent copper (Property File - American Bullion [1992-08-20]: Assay Certificate - 2V-0817-RA1 - Carmi Area).
This was an active exploration camp at the turn of the century, when the Highland Bell (MINFILE 082ESW030) silver mine was discovered. Early references indicate a 12-metre shaft was sunk in an "iron cap" on the Knob Hill claim in 1901. This claim was Crown granted as Knob Hill (L.2659) in 1903. Numerous old workings, trenches, pits and open cuts occur in the general area of Mullins Hill. Those to the northeast are grouped under the Rosemont (MINFILE 082ENW046) occurrence 1.5 kilometres away, and those to the south are grouped under the Ivy (MINFILE 082ENW037) occurrence, which is located approximately 2 kilometres to the south.
In 1975, Vestor Explorations Ltd. drilled two percussion drill holes along the road immediately west of Mullins Creek. This was followed by three percussion drill holes in 1976. No results were filed in the assessment reports. In 1992, American Bullion examined the area.