The Tuk occurrence is located on the northern part of the Klastline Plateau about 10 kilometres west-southwest of the town of Iskut. The area was staked as the Tuk claim in 1989 and the showing was discovered in 1990. A few rocks, soils and silt samples were taken in 1990 with some follow-up in 1991.
The region is mapped as Unit Javb (Open File 1997-03) of the Lower Jurassic Hazelton Group. This unit consists of andesitic volcanic breccias and conglomerates. These are described as grey-green and maroon, feldspar hornblende-porphyritic andesitic to dacitic debris flows and lahars; minor flows; with intervals of green and maroon epiclastic conglomerate and medium to coarse-grained crystal lithic wacke with angular, red mudstone fragments. The Tuk claim rocks are described as andesite flows cut by a medium- to fine-grained hornblende diorite plug or dike.
Calcite-quartz veining containing disseminated chalcopyrite, malachite, azurite and pyrite were located along a ridge top. The quartz veins are typically 2 centimetres wide but may be up to 20 centimetres wide and traceable over 100 metres. Most veining occurs in andesite flow rock near the diorite contact. Samples yielded up to 7.5 per cent copper, 5.8 grams per tonne gold, 11.7 grams per tonne silver and anomalous molybdenum values (Assessment Report 20687, page 5).
A sample of andesitic rock containing quartz vein with 5 per cent chalcopyrite was taken about 200 metres southwest of the plotted location of the Tuk showing (Sample 399153, Assessment Report 27737).
Recent geological mapping by Colorado Resources (2017) suggested that rock alteration is associated with enhanced gold and copper geochemistry, with multiple intrusive phases and brittle deformation zones. The Castle Alteration Zone (CAZ) forms a slightly arcuate shaped east-west-trending corridor which has a strike length of approximately five kilometres. The CAZ continues to the eastern property boundary and is overlain to the west by younger volcanic cover. Within the CAZ, rock alteration is characterized by both enhanced QSP (quartz-serricite-pyrite) and locally potassic alteration. Mineralization has affinities to both porphyry gold-copper systems and intermediate sulphidation structurally controlled gold-silver veins. Potassic altered host stockwork quartz and/or magnetite veins often contain fine to coarse disseminated or lens/band shaped occurrence of chalcopyrite. Phyllic altered rocks often have high concentrations of gold associated with both increased chalcopyrite and pyrite proportions.
Merged data from the 2017 program of Colorado Resources along with historic soil samples (1,242 soil samples) are illustrated in figures 2 and 3 available on-line as part of the Colorado Resources, January 5, 2018 News Release (www.coloradoresources.com/projects/bc-properties/kinaskan-castle-property/maps-sections/). Figure 2 shows how anomalous gold-in-soil geochemical data closely track the Castle Alteration Zone (CAZ). Gold geochemistry over 200 parts per billion (ppb) gold in soils forms a series of well-defined segments, from a few hundred metres to over 600 metres in strike length within the broader CAZ.
Data and interpretation by Colorado Resources in 2017 indicate that the TUK showing (104G 162) occurs between two smaller 300 parts per million copper-in-soil anomalies (smaller than those at Castle East (104G 253)). One of these areas occurs to the immediate southwest and the other to the immediate north of the plotted TUK MINFILE location. No significant gold-in-soil anomaly is coincident with the copper-in-soil anomaly, however a cluster of grab samples in the area yielded values from less than 0.5 gram per tonne gold up to 2 grams per tonne gold (Colorado Resources, January 5, 2018 News Release).
In 2018, Colorado extended induced polarization survey coverage on the property that produced chargeability anomalies coincident with large gold and copper soil geochemical anomalies, which extend along an east-west trend for more than 2000 metres. The anomalies are interpreted to be sourced from underlying early Jurassic monzodiorite porphyry intrusive (+/-volcanic) rocks, potentially similar in age and lithology to those described as the same rock units that host the Saddle North and Saddle South discoveries on the Tatogga property to the immediate east (see 104G 432 and 433).
Late in 2019 Colorado Resources conducted 1555 metres of drilling at the East Castle zone (104G 253 and 254) targeting coincident gold and copper anomalies (detected from sampling) and chargeability anomalies. At the new Moat target, anomalous gold and pathfinder values were outlined in soil samples, only 350 metres from the Saddle South gold-silver deposit of GT Gold. At the new Moat target, anomalous gold and pathfinder values were outlined in soil samples, only 350 metres from the Saddle South gold-silver deposit of GT Gold.
At the new Moat anomaly, located just over 1 kilometre east of Tuk, soil sampling returned anomalous values over a width of 250 metres with coincident anomalous gold (to 649 parts per billion), silver (to 16.8 parts per million) along with anomalous copper, arsenic and antimony values. The anomaly is indicative of a polymetallic vein gold-silver setting, and occurs along the eastern claim boundary between the Castle property and the adjoining Tatogga property of GT Gold Corp. The anomalous Moat soils occur within 350 metres of the nearest drill holes at the Saddle South gold-silver prospect, and less than 200 metres from talus fine samples reported by GT Gold that assayed up to 40.3 grams per tonne gold (GT Gold Investor Presentation, November 2019). A cluster of significant (up to 5.8 grams per tonne gold) gold-in-bedrock samples are located about 1200 meters west of the Moat soil anomaly as shown on a “Moat Target” figure reporting “Gold in Rock and Soil” (https://www.coloradoresources.com/projects/kinaskan-castle-property/maps-sections/). These rock samples are "2019 and older" and are located in the Tuk occurrence area.
See Castle (104G 076) and Castle East (104G 253) for further details of the Castle Alteration zone and related work history.
