The Lake Adit occurrence is located on the west side of Lillooet Lake to the southeast of Mount Currie, in the steep and precipitous terrain of the Pacific Ranges.
Regionally, the area is situated on the southwest flank of the Jurassic to Cretaceous Coast Crystalline belt, composed of granite, granodiorite, quartz monzonite and quartz diorite.
Locally, the is underlain mainly by a roof pendant composed of metamorphosed volcanics, sediments and intrusions of the Upper Triassic Cadwallader Group and greenschist metamorphic rocks of the Cretaceous to Tertiary Slollicum Schist. The Cadwallader Group consists mainly of andesitic greenstone, tuffs and flows; rhyolitic tuffs and flows with minor limestone lenses, argillite, phyllite, conglomerate and chert. Contact metamorphism is evident along or adjacent to limestone-volcanic contacts, by the development of skarn.
Mineralization consists of massive to semi-massive magnetite skarn at the contact of limestone with massive, dark-green andesitic to dacitic flows, rhyolitic tuffs and feldspar porphyry volcanic andesite over 2 to 5 metres width. The limestone is white to light- grey, recrystallized and fine-grained. Within the skarn the dominant sulphide mineral is pyrite, along with chalcopyrite, pyrrhotite and minor sphalerite and galena. Malachite and azurite occur on weathered exposures of skarn. Magnetite is also abundant. Mineralization has been traced for 200 metres along a north-northwest trend. Propylitic alteration (epidote and chlorite), silicification and pyrite-pyrrhotite-magnetite mineralization are commonly along the sheared contact in the vicinity of the Lake Adit prospect. A lamprophyre dike exposed in the Lake Adit appears to have no effect on mineralization.
Based on textural evidence, two episodes of mineralization are present: 1) ubiquitous diagenetic pyrite (30 to 20 volume per cent) and 2) epigenetic pyrite ± chalcopyrite and sphalerite as bands, disseminations and fracture fillings. The second phase of mineralization is spatially related to increased sericite, pyrite ± chlorite, calcite and/or epidote, chlorite, pyrite ± calcite and magnetite.
In 1980, a 2.4-metre channel sample assayed 2.8 per cent copper, 0.01 per cent lead, 1.86 per cent zinc, 0.9 gram per tonne gold, 40 grams per tonne silver and 34.8 per cent iron (Assessment Report 9003). A 1986 to 1987 diamond drill hole located near a strong electromagnetic conductor intersected copper-zinc-gold-silver mineralization that persisted to 8.5 metres depth (Assessment Report 23366). A nearby outcrop, consisting of a coarse fragmented rhyolite cemented by sulphides, suggests close proximity to a volcanic vent.
In 1987, a diamond drill hole (DDH-4) intercepted 4 metres of massive sulphide mineralization yielding from 0.25 to 0.43 per cent zinc, 0.1 to 1.3 per cent copper and 1.4 to 10.3 grams per tonne silver (Property File - Green Lake Resources Ltd. [1987-03-01]: Filing Statement #74/87 - Lill)
In 1988, assay ranges of 40 channel samples yielded from 0.01 to 10.1 per cent zinc, 0.21 to 2.87 per cent copper, trace to 23.9 grams per tonne silver and trace to 3.1 grams per tonne gold (Property File - Green Lake Resources Ltd. [1988-03-29]: News Release - Winter Programs completed on Lill, Golden Plug and Native Properties). Also at this time, a diamond drill hole (88-1) from the Lake zone yielded up to 0.28 per cent copper, 1.34 per cent zinc and 4.4 grams per tonne silver over 6 metres, including 2.34 copper, 0.83 per cent zinc and 22.2 grams per tonne silver over 0.3 metre and 0.29 per cent copper, 28.60 per cent zinc and 4.8 grams per tonne silver over 0.2 metre (Property File - Green Lake Resources Ltd. [1988-03-29]: News Release - Winter Programs completed on Lill, Golden Plug and Native Properties).
In 1992, a rock chip sample across a road cut exposing a 1-metre wide shear zone yielded 9.99 per cent copper, 0.11 per cent lead, 0.51 per cent zinc, 290.74 grams per tonne silver and 6.72 grams per tonne gold (Assessment Report 23366). A sample of heavily mineralized skarn from the Lake Adit occurrence yielded 9.07 per cent copper, 0.32 per cent zinc, 116.57 grams per tonne silver and 0.78 gram per tonne gold (Assessment Report 23366).
In 1994, seven mineralized zones were identified between the Lake Adit and Eagle (MINFILE 092JSE008) occurrences. At the Lake Adit occurrence, the average of nine rock chip samples over 1 to 2 metres yielded up to 0.45 gram per tonne gold, 38.3 grams per tonne silver, 1.67 per cent copper and 0.70 per cent zinc (Assessment Report 23366). Five metres above the Lake Adit portal, chip sample FR-6 yielded 0.79 gram per tonne gold, 26.9 grams per tonne silver, 1.4 per cent copper and 1.0 per cent zinc. Ten metres above the Lake Adit portal, chip sample FR-5 yielded 0.41 gram per tonne gold, 33.9 grams per tonne silver, 0.6 per cent copper and 0.3 per cent zinc. Several semi-massive to massive sulphide lenses were found along the limestone-volcanic contact, 44 metres northwest of the Lake Adit prospect. Chip sample FR-2, across 20 centimetres, yielded 0.38 gram per tonne gold, 18.3 grams per tonne silver, 2.0 per cent copper and 0.8 per cent zinc. Massive sulphide skarn mineralization was located 49 metres from the Lake Adit portal. Chip sample FR-3, across 1 metre, yielded 0.11 gram per tonne gold, 11.1 grams per tonne silver, 0.4 per cent copper and 0.2 per cent zinc. At 135 metres northwest of the Lake Adit portal, massive pyrite, pyrrhotite and magnetite are hosted in andesite. Chip sample FR-10 yielded 0.06 gram per tonne gold, 2.2 grams per tonne silver, 0.7 per cent copper and 0.5 per cent zinc.
Five diamond drill holes were also drilled in 1994 to test the contact between an induced polarization chargeability and resistivity high anomaly and an adjacent magnetic anomaly. Drill hole LA 94-4 yielded the most significant copper, zinc, silver and gold values. The 2.5-metre interval between 346.5 and 349.0 metres yielded 0.85 per cent copper, 0.38 per cent zinc, 7.0 grams per tonne silver and 0.1 gram per tonne gold (Assessment Report 23693). The remaining drill holes intersected copper values, ranging from 0.02 to 0.04 per cent, and zinc values ranging from 0.11 to 4.50 per cent (Assessment Report 23693).
The Lake Adit prospect was first discovered in 1915. Considerable work has been done on the property by a number of companies, and has been concentrated on two areas: the Lake Adit and Eagle (North Eagle, MINFILE 092JSE008) occurrences. A single adit was originally driven on each occurrence between 1915 and 1923. Open-cuts, shallow pits and several copper showings were excavated between the two adits. Regional mapping by Cairnes in 1924 revealed the Lake Adit prospect was hosted within a regional mineralized zone 5.6 kilometres long and 200 metres wide. In 1929, Howe Sound Company drilled three diamond- drill holes beneath the Lake Adit prospect. In 1969, the Lake Adit prospect and surrounding area were explored by Cerro Mining Company of Canada Ltd. In 1980, H. Kim, consulting for Regulus Resources Inc., channel sampled the Lake and Eagle adits. In 1985, Lawrence Mining examined the property. During 1986 through 1988, Green Lake Resources Ltd. completed a detailed exploration programs, including rock and soil sampling, geological mapping, geophysical surveys and diamond drilling on the area as the Lill claims. In 1990, British Columbia Geological Survey geologists mapped a new roadcut along Lillooet Lake and near the Lake Adit prospect. In 1992, A. Kikauka conducted an exploration program in the vicinity of the Lake Adit prospect. In 1994, Guardian Resources Corp. requested Ashworth Exploration conduct exploration on the Lake Adit prospect.