The Slocomb 101 occurrence is located 2.25 kilometres south of Mount Slocomb and 3.0 kilometres east of Spinel Lake, in the north-central Sifton Ranges of the Omineca Belt approximately 255 kilometres north of the community of Germansen Landing.
The Sifton Ranges lie within the northern Omineca Belt which is bound to the east by the Northern Rocky Mountain Trench and Foreland Belt, and to the west by the Intermontane Belt. The northern Omineca Belt is composed of Precambrian crystalline basement, mid-Paleozoic miogeoclinal strata and Paleozoic to Mesozoic volcanogenic rocks, which are in turn intruded by Cretaceous and younger plutons.
The core of the Sifton Ranges is a moderately inclined, west-verging, elongate and domed anticlinorium. Lithologies consist of Hadrynian Ingenika Group metaquartzite, paragneiss, marble and pelitic schist. Doming was caused by uplift in the mid-Cretaceous and Eocene. Mineral assemblages and geothermobarometry indicate amphibolite facies metamorphism. Synmetamorphic deformation resulted in a strong foliation parallel with the bedding which, in the Sifton Ranges, is isoclinally folded (Geological Survey of Canada Bulletin 376). The gently east dipping Sifton fault truncates isoclinal and upright folds and metamorphic isograds. Movement on the Sifton fault postdates the peak of metamorphism (mid-Jurassic?) and predates the intrusion of Eocene granite. Hangingwall rocks have been tentatively included in the Ingenika Group, although their metamorphic and structural history differs from the footwall rocks. An undeformed Eocene granite cuts the Sifton fault at the south end of the Sifton Ranges (Assessment Report 19583).
Locally, the geology surrounding the Slocomb 101 showing is divided into two packages which are separated by the Sifton fault. Those in the footwall of the Sifton fault are part of the Lower Plate and those of the hangingwall are part of the Upper Plate. The Lower Plate rocks form the core of an antiform and consist of (from the core outward) rusty weathering metaquartzite (unit Hlq); paragneiss and pelitic schist (unit Hlp); pure marble and calcsilicate rock (unit Hlm); pelitic schist (unit Hlps); and pelitic schist, metagrit, psammite and marble (unit Hlg) (Geological Survey of Canada Bulletin 376).
Limited exposures of Upper Plate stratigraphy are also evident near the Slocomb 101 showing. These include pure metaquartzite, amphibolite, minor pelitic schist, feldspathic metaquartzite, and paragneiss (unit Hlqa); quartz lens schist, psammite and marble (unit Hlsm); and rusty weathering pelitic schist, minor psammite, and marble (unit Hlws) (Geological Survey of Canada Bulletin 376). For a more detailed description of each of these units from the Lower and Upper Plates refer to Assessment Report 19583.
The greatest volume of sulphide mineralization is found in units Hlm and Hlg, on the west side of the antiform. Pyrrhotite and lesser pyrite occurs in thin lenses, 10 centimetres to rarely 1 metre thick, at marble/calcsilicate and marble schist contacts, and within calcsilicate rocks. The sulphides are predominantly associated with fine to medium grained, dark green to black pyroxene skarn. The mineral content of the majority of the exposures varies from 10, to in excess of 80 per cent. Sphalerite, in minor quantities, is the most abundant economic sulphide. It is usually accompanied by argentiferous galena or, rarely, by chalcopyrite. Semicontinuous exposures of disseminated and massive pyrrhotite and pyrite, up to 350 metres in length, are associated with the two marble members of unit Hlm. The two marble members are each 20 to 30 metres thick with about 20 metres of quartz mica schist and calcsilicate rocks between them. Refer also to the other Slocomb occurrences (094E 223-227).
In 1989, sample 27718 was taken at the Slocomb 101 showing between the two marble members of unit Hlm and consisted of 10 to 20 per cent pyrrhotite in calcsilicate +/- muscovite (+/- garnet) schist. Analytical results for this sample were 9.51 per cent lead, 0.46 per cent zinc and 30.86 grams per tonne silver (Assessment Report 19583).
No assessment reports have been filed for work in the vicinity of the Mt. Slocomb property prior to 1988. In 1984, Suncor Inc. conducted a reconnaissance geochemical sampling program collecting 180 stream sediment and 29 rock samples. All were analyzed for gold and silver, and some for copper, lead and zinc. Imperial Metals staked part of the present property in 1986, but the extent of their work is unknown. In November, 1987, the Slocomb 1-4 mineral claims were staked for Hillsborough Resources Ltd. These were followed by the Slocomb 5-32 claims in January, 1988 and the Harmonnie I-V claims in August, 1988. Derry, Michener, Booth and Wahl were retained by Hillsborough to conduct an exploration program on the Slocomb claims and between mid-June and August 25, 1988, they established a camp on Spinel Lake, collected 1249 sediment samples and 1491 soil samples, mapped most of the ridges and prospected the obvious rusty zones. A combined magnetometer/VLF-EM survey was flown, and aerial photographs taken from which 1:5000-scale orthophotos were produced. No significant mineralization was found.
In early 1989, Cordilleran Engineering Ltd. was asked to evaluate the results of the 1988 exploration program, and subsequently was retained to propose and supervise an exploration program to determine if there were potential mineral deposits on the Mt. Slocomb property. The 1989 program, based partly on the results of the 1988 work, consisted of establishing nine soil sample grids, collecting 2913 soil, 114 stream sediment and 494 rock samples, mapping and prospecting all the marble/calcsilicate/skarn horizons, and conducting a limited magnetometer survey over the area found to have the most significant base and precious metal values.
