The ROWBOTTOM porphyry copper prospect is 4.2 kilometres east of Mount McClure, approximately 148 kilometres southwest of Williams Lake, B.C.
The prospect is within Late Cretaceous plutonic rocks of the Coast Plutonic Complex, 3 kilometres south of its contact with Upper Cretaceous volcanic and volcaniclastic rocks of the Powell Creek Formation.
The hostrock is hornblende-biotite granodiorite that is locally cut by post mineralization hornblende-plagioclase porphyry dikes. Mineralization occurs in two shear zones that are 5 to 6 metres wide and approximately 100 metres apart. The shear zones strike north-northeast and dip steeply east. Within the shear zones, the hostrock is altered (propylitic and sericitic alteration) and cut by numerous parallel quartz stringers. The quartz and altered rock contain disseminated pyrite, chalcopyrite, molybdenite and minor pyrrhotite. A sample from the upper zone assayed trace gold, 4.8 grams per tonne silver and 0.41 per cent copper (Geological Survey of Canada Summary Report 1928).
In 1970, Sumitomo Metals Mining is reported to have mapped copper-molybdenum mineralization in bedrock for 547 metres along Rowbottom Creek. In that year, the best intersection from 11 percussion drill holes graded 0.41 per cent copper and 0.034 per cent molybdenum (Assessment Report 19565). Lead, silver and zinc mineralization has since been reported in quartz veins southwest of the Rowbottom zone on the southern slopes around Rowbottom Creek.
Soil and rock sampling at the Rowbottom area in 1991 successfully identified copper, gold, silver, molybdenum and lead anomalies (Assessment Report 21985).
In 2011, Granite Creek Gold Ltd. conducted a small rock sampling program. Mineralization consisting of disseminated pyrite, chalcopyrite, sphalerite and galena reported low-grade values of copper, lead and zinc with up to 1.22 grams per tonne gold and 14.1 grams per tonne silver (Assessment Report 33392).
During 2014 through 2019, Amarc Resources Ltd. completed programs of geological mapping, geochemical (talus fines, rock chip and stream sediment) sampling, 163.6 line-kilometres of induced polarization surveys, 1069 line-kilometres of airborne magnetic surveys and 18 157 metres of diamond drilling on the area as part of the IKE project. The majority of the drilling (15 455.34 metres in 26 holes) was completed on the IKE (MINFILE 092O 025) occurrence. The ROWBOTTOM prospect lies within Amarc's Empress high-grade copper-gold-silver deposit area (PR REL Jan 19, 2021). Geological mapping around the ROWBOTTOM occurrence was conducted in 2014 (Assessment Report 35307), followed up by eight wild-cat exploration drill holes in 2017, and more mapping and geophysical assessment in 2018. One hole (RB17001) intersected significant intervals of porphyry copper-molybdenum mineralization hosting elevated silver and gold values (Assessment Report 37517).