The Castle East area is underlain by of the Lower Jurassic Hazelton Group (Unit Javb, Open File 1997-03) consisting of andesitic volcanic breccias and conglomerates. The Hazelton rocks unconformably overlie or are in fault contact with Stuhini Group sedimentary rocks to the south.

The Castle Alteration Zone (CAZ) of the Castle property closely tracks the east-west strike orientation of a weakly arcuate shaped, highly elongate monzodiorite. The central intrusive core of the CAZ is formed from an intrusive body which ranges in width from approximately 200 to 500 metres. This intrusion has a known strike length of approximately 5 – 6 kilometres. It is terminated to the east only by the eastern property boundary of the Castle property and to the west by a much younger Neogene volcanic cover. These intrusions have macroscale characteristics similar to other monzonites and monzodiorites in this district which range in age from approximately 205 to 215 Ma. Recent Re-Os dates by van Straaten (2017) date the main monzodiorite intrusions at Castle as 206.1 +/- 0.9 Ma, within that time fram of an important porphyry copper – gold event in the Iskut area.

Pyrite occurs as disseminations generally making up 5 to 8 per cent of the Castle trend alteration zone. Local higher concentrations (up to 15 per cent) occur along the narrow structures. Local higher concentrations (up to 15 per cent) occur along the narrow structures. Quartz-pyrite veins contain up to 30 per cent pyrite. Isolated exposures of malachite, chalcopyrite and minor bornite, specularite and molybdenite occur with pyrite. The copper is generally associated with later quartz-carbonate and barite veining or calcareous andesitic volcanic rocks and also occurs in silicified zones proximal to the pyrite-sericite-quartz bearing structures. Chalcopyrite also occurs with a quartz-pyrite veinlet.

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.

At the Castle Central, a 1.5 metre chip of silicified andesite assayed 1.48 grams per tonne gold (Assessment Report 25432).

The best interval from 2019 drill hole CAE 19-04 at Castle Central was 1.1 metres (from 56.5 to 57.6 metres depth) of 1.63 grams per tonne gold with no copper (Colorado Resources Ltd, News Release, December 9, 2019).

Work History.

The Castle #l and Castle #2 claims, totalling 27 units, were staked by Teck in 1980 as part of a regional program. After limited soil sampling and mapping it was found that geochemical anomalies in gold, silver and copper were associated with a large, heavily pyritized zone in volcanic rocks. The Castle #1 was allowed to lapse. In 1985, hand trenching, chip sampling, magnetometer, self potential and VLF surveying yielded positive results with gold values up to 8.2 grams per tonne gold over 3 metres. The CAS 1 to CAS 4 claims were added in 1987. The A9 area is encompassed by the Cas 2 claim as are the Castle East and Castle Central Zone. The Castle zone (104G 076) or the Main zone occur to the west on Castle #2 claim

In 1989, Ascot Resources Ltd. carried out a detailed silt geochemical sampling program over the entire Klastline Plateau that resulted in the staking of the 20 unit TUK claim to cover an anomalous drainage and colour anomaly about 2500 meters east of the Castle showing. In 1990 and again in 1991, Ascot carried out small prospecting and geological mapping programs along with silt and contour soil sampling which in part covered the northeast comer of the TUK 1 claim before allowing the claims to lapse.

In 1997, work by Teck Corporation consisted of 1:10,000 scale mapping of the property and mapping with concurrent rock sampling on the poorly explored and previously, largely unsampled Castle East Zone, which hosts the widest extent of alteration on the property, and on the Castle Central Zone (Assessment Report 25432). The higher gold values were obtained from quartz-carbonate-chalcopyrite veins, quartz- pyrite veins and in silicified zones, commonly associated with the pyrite-sericite-quartz bearing structures. The maximum values obtained were only 1.5 grams per tonne Au over 3.0 metres, 2.34 grams per tonne Au over 1.5 metres (Assessment Report 25432).

In 2002, Viceroy Resource Corporation staked the TUK 1 claim immediately east of a claim covering the Castle Mineral showing (Castle Main) and trend. The TUK 1 covers the southwestern portion of the old TUK claim and the northern half of Teck's Cas 1 claim.

In February of 2017, a 100 per cent interest in the Castle portion (163.72 square kilometres) of the larger Kinaskan (163.72 square kilometres) claim block was acquired by Colorado Resources Ltd from Kaizen Discovery Inc. During the 2017 field program Colorado Resources collected 856 “B” horizon soils samples and a total of 191 rock samples. An IP survey was run on north south lines between the Castle and Castle Central occurrences and 1 line just east of the Castle Central MINFILE plot.. In addition to the ground induced polarization program, an airborne magnetic survey was also carried out covering some 145-line kilometres. Samples taken close to the Castle Central occurrence were not significant in gold except for 3 taken about 400 metres to the southeast and copper was not significantly elevated.

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).

In 2019, porphyry-style mineralization was discovered at Castle East. Late in 2019 Colorado Resources completed 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.

Three of the drill holes, CAE 19-01, CAE 19-02 and CAE 19-03, are located from 200 to 400 metres east of the Castle East MINFILE plot with the fourth, CAE 19-04, located about 50 metres northwest of the Castle Central MINFILE plot. Three of four holes intersected broad copper-gold-molybdenum values in what is thought to be the pyritic outer shell of a porphyry system, for example: DDH CAE19-01 intersected 14.9 metres grading 0.10 per cent copper and 0.52 grams per tonne gold. DDH CAE19-02 intersected 248.2 metres grading 0.07 per cent copper, including 22.8 metres grading 0.15 per cent copper and 0.0053 per cent molybdenum (Colorado Resources Ltd, News Release, December 9, 2019).

See Castle (104G 076) and Castle East (104G 253) for further geological and work history details.