The Mulligan occurrence(s) are located along Ray Creek, a tributary of the Stawamus River, and extend along the north western flank of Mount Mulligan.
Regionally, the area occurs on the eastern edge of the Britannia-Indian River pendant, which hosts the volcanogenic deposits of the Britannia camp (MINFILE 092GNW003). The Britannia-Indian River pendant is mainly a calc-alkaline, sub-aqueous volcanic and sedimentary sequence of felsic to intermediate pyroclastics, flows, cherts, argillites and greywackes. The entire pendant has been classified as Upper Jurassic to Lower Cretaceous Gambier Group. Cenozoic to Mesozoic Coast Plutonic Complex intrusives surround portions of the stratified rocks creating screens or pendants. These bodies are oriented north- westerly throughout the Coast complex. Pliocene to recent Garibaldi Group basaltic dykes and sills intrude both the pendant and plutonic rocks.
The area is underlain by northwest- trending andesitic to intermediate tuffs and fragmental rocks, and felsic flows and tuffs of the Gambier Group in contact with granodiorite of the Coast Plutonic Complex. Garibaldi Group mafic dykes intrude all units. Ten volcanic units are mapped on the property and include a sequence of intercalated aphyric rhyolite, andesite tuff, poly-lithic fragmental rock and intermediate lapilli ash tuff. The poly-lithic fragmental unit occurs as a broad band across the central portion of the property. A second sequence comprises numerous intercalated felsic tuffs and minor argillite. These tuffs are all rhyolitic in composition but can be distinguished as aphyric, quartz crystalline, feldspar crystalline, quartz-feldspar crystalline and ash tuff units. Locally, flow banding and ash bands indicate a northwest strike.
The volcanic succession is a tilted sequence striking approximately 120 degrees with moderate to steep southwest dips that average 60 degrees. Graded bedding indicates an overturned sequence with stratigraphic tops to the north. A regional foliation striking approximately 154 degrees and dipping 78 degrees has been imposed on the volcanic rocks and is strongest in shear zones.
Numerous north –to- northwest –trending, sub-vertical shear zones are evident in three main areas. Zone widths vary from 2 to 5 metres. Faulting is prevalent and is related to the granodiorite intrusive contact. Shearing and faulting of the granodiorite and volcanics at the western margin of the property has created a complex structural relationship between the volcanic units.
Four alteration facies are recognized: quartz-sericite; silicification; sericitization; and epidotization. Quartz-sericite alteration is associated with the north- trending shear zones. These zones are up to 5 metres wide and the intensity of alteration increases towards the centre of the shear, producing a quartz-sericite schist. Stockwork silicification is evident in intermediate lapilli ash tuff and varies in intensity from moderate to strong. Individual quartz veins are up to 4 centimetres wide. Moderately intense sericitization of the poly-lithic fragmental unit is restricted to the matrix and rims of fragments. Epidote occurs as blebs in andesite tuff.
Locally, mineralization occurs in an altered zone 304 metres wide and 1432 metres long. The area is roughly parallel to the north west contact of the Coast granodiorite contact. Two types of mineralization are identified.
The first type consists of pyrite mineralization associated with north- trending, sub-vertical shears. Discrete pods to lenses, less than 50 centimetres wide, occur in a quartz-sericite schistose gangue locally found within the shears. Disseminated pyrite mineralization increases in intensity towards the centre of the shears and is discontinuous along strike. In 1983, two rock samples (25592 and 25593) yielded up to 1.0 gram per tonne gold, 14.4 grams per tonne silver, 0.141 per cent copper and 0.883 per cent zinc (Property File - Kidd Creek Mines Ltd. [1984-01-01]: 1983 Final Report on the Mulligan Property). In 1987, sampling yielded up to 1.45 per cent copper, 0.05 per cent zinc, 0.01 per cent lead and 9.9 grams per tonne silver (Assessment Report 16495).
The second type of mineralization, as exposed by trenches and stripping to the east on the Crane claim, consists of disseminated chalcopyrite and sphalerite associated with very intense stockwork silicification in intermediate, clast-supported lapilli ash tuff. The clasts consists of cherty rhyolite and altered intermediate volcanics. The zone strikes 050 degrees and dips 80 degrees east. In 1987, sampling yielded up to 2.04 per cent zinc, 0.22 per cent copper, 0.08 per cent lead and 3.5 grams per tonne silver from an isolated exposure (Assessment Report 16495).
The area has been explored since the early 1900’s as the Bruce, Radiant and Contact groups with several open-cuts, three short adits and three shallow vertical shafts dating to that period. In 1927, seven diamond drill holes were completed. In 1929, Radiant Copper Limited completed a electromagnetic survey of the area identifying a number of weak conductors related to pyritic shear zones. Later work focussed on the Crane claim, located at the head of the Ray Creek basin, and included three diamond drill holes. Results were reportedly ‘un-encouraging‘.
In 1977, Texasgulf Inc. staked the Mulligan 1 claim and performed minor cat trenching. The following year, a program of geological mapping, silt and soil sampling and electromagnetic surveys was completed. In 1983, Kidd Creek Mines (formerly Texas Gulf) performed a program of soil and rock sampling, geological mapping and ground magnetic and induced polarization surveys on the Mulligan 1 claim. In 1987, a further program of geological mapping and rock sampling was completed.
