The Red Cliff mine is on the west bank of Lydden Creek, immediately west of the confluence of American Creek and the Bear River, 19 kilometres north of Stewart. The portal to a lower, 425 metre long access tunnel (700 level) is at an elevation of 146 metres and is located on the east bank of Lydden Creek, about 700 metres west of the Stewart highway. Two portals (North and South) access the 1000 level and are located on the west bank of Lydden Creek, about 500 metres north-northwest of the portal of the lower tunnel. A fourth portal (Upper portal) lies about 30 metres above the North and South portals.
The area is underlain predominantly by north striking, west dipping andesitic tuffs, agglomerates and minor flows of the Lower Jurassic Unuk River Formation (Hazelton Group) (Bulletin 58; 63). Immediately east of Lydden Creek, a conformable body of amygdaloidal feldspar porphyry, containing phenocrysts of feldspar and augite, may represent a sill or a flow. Tertiary(?) quartz monzonite, diorite and hornblende porphyry dikes are common. These trend northwest and northeast and are part of the Portland Canal dike swarm (Bulletin 58). The area is intensely fractured and faulted. North trending, west dipping dipslip faults are most conspicuous and appear to be younger than east trending faults.
Mineralization comprises irregular veins and pods of quartz, pyrite, chalcopyrite and minor sphalerite. The orebodies, irregular and lenticular, are commonly enclosed in weakly developed sericitic alteration. The largest orebody, 76 metres long and averaging 6 metres in width, occurs on the 700 level.
Most of the mineralized pods appear to lie along locally east trending, steeply dipping shears that transect all rock types except the diorite dikes. The mineralization is most conspicuous adjacent to, and on the hangingwall of, a prominent north trending, west dipping fault along Lydden Creek.
Estimated reserves for the Red Cliff deposit are reported to be 18,856 tonnes of sorted ore grading 3.19 per cent copper and 2.8 grams per tonne gold (J.L. Parker, 1912; cited in Assessment Report 17465, page 35).
The Red Cliff group (Red Cliff, Montrose (104A 033), Mount Lyell (Lot 77), Little Pat (104A 062), Waterloo (104A 033) and Mac and Dot Fractions) were originally held by Lydden, Pederson, McDonald and Peardon who did some opencutting and drove tunnels in 1908. Apparently, other zones were discovered at the same time (Montrose, Waterloo). That year the property was sold to A.E. Smith, who formed the Red Cliff Mining Company. Between 1908-12, about 2385 metres of underground development was carried out on five(?) levels on the Red Cliff mineralization, including four portals, a long access tunnel and raises. The Red Cliff mine was the first significant mine in the Stewart area; it was linked to Stewart by road and rail. About 200 tonnes of ore grading 5 per cent copper was stockpiled in 1910; an additional 1.4 tonnes was shipped to the Tyee smelter and yielded 8.25 per cent copper, 83.7 grams per tonne silver and $5 per ton gold (1910 prices). In 1912, upon completion of the railway, a further 1133 tonnes of ore was shipped to the Tacoma smelter and another 2030 tonnes was placed on ore dumps. A total of 2411 grams of gold and 40,100 kilograms of copper was recovered. The mine closed in 1912. The property remained idle until 1921, when Trites, Woods and Wilson purchased the property and carried out minor work on the Montrose and Waterloo zones. Little further work was reported until 1939, when H.D. Haywood purchased the claims from the estate of Wilson. That year a camp and trail were built and during 1939-40 Haywood worked on the Montrose zone; about 40 tonnes of ore were shipped from the Montrose zone during this period. In 1941, 10 tonnes (averaging 9.23 per cent copper, 1.09 per cent zinc, 8.9 grams per tonne gold and 75.4 grams per tonne silver) was high graded from the 700 level(?) of the Red Cliff deposit and a 19.3 tonnes of ore was high graded from the Montrose zone. In 1946, the Yale Mining Company, Limited optioned the property and sampled the Montrose and Waterloo zones. In 1950, Yale Lead and Zinc Mines Limited completed about 600 metres of drilling on the Montrose(?) zone. n 1959, Oro Fino Mines Ltd. optioned the property; no work was reported. In 1968, International Mogul Mines Limited acquired the property through amalgamation of several companies, including Yale Lead and Zinc. In 1972, Citex Mines Ltd. acquired a three year lease on the property from International Mogul and subsequently entered into an agreement with Adam Milling Ltd. The latter company built a 110 tonnes-per-day mill at the mouth of Bitter Creek and reopened the Red Cliff mine in April, 1973. The 700 level was rehabilitated and open stoping commenced. However, due to unsafe conditions, the Ministry of Mines closed the mine in September, 1973. Apparently, 3768 tonnes of ore were shipped to the mill from the mine and old dumps (this tonnage may include some ore from the Roosevelt deposit (104A 069)). Some drilling was also reported in area of the Red Cliff deposit that year. Little further work has been reported since 1973. In the late 1970s, limited work was done underground and, in 1979, Page and Skimming carried out sampling on the Red Cliff, Montrose and Waterloo zones. In 1987, Joutel Resources Ltd. entered into a joint venture agreement with B.L. Carlson and V.N. Harbinson on the Red Cliff claim group and staked two grid claim blocks. That year Joutel conducted a comprehensive program, focusing mainly on the Montrose and Waterloo zones, comprising trenching, geological mapping, soil, silt and rock sampling and diamond drilling (six holes totalling 1007 metres) on the Montrose and Ridley Road zones.