The A9 and A8 showings are located on the northern part of the Klastline Plateau about 11 kilometres west-southwest of the town of Iskut. These two small copper showings were located by members of the B.C. Geological Survey Branch during a mapping program in 1996.
The showings occur in an area mapped as Unit lJavb (Open File 1997-3) 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 A8 showing consists of a 0.5-metre wide gossan where 5 per cent disseminated chalcopyrite occurs in andesitic breccia/wacke. Malachite stains were also observed. A sample assayed 2 per cent copper and 0.11 gram per tonne gold (Open File 1997-3, Table 1 (Sample A8, Field Number RMA96-682)).
About 700 metres to the southwest is the A9 showing. Here, a single 1.5-centimetre wide vein with 0.5 centimetre clots of chalcopyrite occurs. A sample assayed 5.9 per cent copper (Open File 1997-3, Table 1 (Sample A9, Field Number RMA96-684)).
The A9/A8 area was covered by Teck Corp's Cas 1 claim in the late 1980s and late 1990s. In 2002, Viceroy Resource Corporation staked the TUK 1 claim immediately east of the Castle showing (104G 076) and trend. The Tuk 1 claims covered the northern half of the Cas 1 claim. In 2004, 3.5 days were spent prospecting along with soil and rock sampling on the TUK 1 claim. See Castle (104G 076) and Castle East (new) to the north for related details. A 2004 sample reported by Viceroy was plotted in the area of the A8 showing northeast of the A9 showing.
In February of 2017, a 100 per cent interest in the Castle portion (10.34 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 airborne magnetic survey was also carried out covering some 145-line kilometres with the A9 zone being at or just south of the survey.
Between September 7th and 21st, 2017 Colorado Resource completed induced polarization and airborne magnetic surveying over parts of the Castle property.The survey consisted of some 10-line kilometers of induced polarization. In addition, 145-line kilometres of airborne magnetic surveying was completed on northeasterly orientated lines utilizing a nominal line separation of some 100 meters. In 2017, four samples taken about 450 metres northeast of the A9 MINFILE plot ranged from 6.2 grams per tonne gold to 22.2 grams per tonne gold (Assessment Report 37464).
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 new Castle South occurrence, immediately south of the A9 showing, is one such chargeability feature. Although soil geochemical result are subdued over the chargeability anomaly, they weakly to moderately anomalous in copper, gold, molybdenum, arsenic and antimony. 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 completed 1555 metres of drilling at the East Castle zone (104G 253 and 254), about 600 metres north of the A9 showing, targeting coincident gold and copper anomalies (detected from sampling and chargeability anomalies).
