Geophysical characteristics of Porphyry Copper Discovery at Tulameen
Leonard W. Saleken, Chairman of Goldcliff Resource Corporation reports that Goldcliff has made the first significant porphyry copper ore grade discovery in the Copper Mountain mining district in decades. With surface samples highlighted by 0.655% copper – almost double the current reserve grades at the Copper Mountain Mine – and 1.3 grams per tonne silver, the Trojan showing is part of the Bolas anomaly, which is located in the Whipsaw target on the Tulameen property in the Copper Mountain mining district near Princeton, BC, Canada. The Tulameen property is 100 per cent owned by Goldcliff.
The three-pronged Bolas anomaly also contains the Eagle showing, which is highlighted by 0.175% copper and 1.0 grams per tonne silver. The copper mineralization on both the Trojan and the Eagle showings is chalcopyrite with malachite, and the iron sulphides are pyrite and pyrrhotite along with magnetite. These showings are situated on surface, above the substantial Bolas deposit-style chargeability anomaly. The Bolas anomaly is 2,000 long by 1,200 metres wide, and merges to form an area of 1.5 square kilometres at about 300 metres.
The Whipsaw alkalic porphyry copper-silver target area is located along the Copper Mountain south-west copper trend, approximately seven kilometres south-west of the Copper Mountain ore bodies. The Copper Mountain mineral reserves are 232,776,000 tons grading 0.36% Cu, 0.09 Au and 1.25 g/t Ag. The Trojan and Eagle showings are associated with the Bolas anomaly, which contains disseminated sulphide mineralization in the 3 to 5% range.
Bolas 3-D IP Anomaly
The deposit-style Bolas chargeability anomaly is a disseminated iron sulphide body that is located near surface and extends to an estimated depth of 500 metres in Upper Triassic Nicola Group rocks. The Bolas anomaly measures approximately 2,000 meters in a northwest direction by about 1,200 meters southwest. At a depth of around 300 meters, the anomaly merges to form a chargeable body of the order of 1,800,000 square meters or 1.8 square kilometres in size. The iron sulphide content of the rocks within the Bolas anomaly is estimated to be 3 to 5%.
The Bolas chargeability anomaly is a three-pronged star feature with a vertex centre and three end nodes that are referred to as the Whip, Elk and Eagle node areas of chargeability. Close to the surface, the chargeability response millisecond (ms) levels are weak to moderate. With increasing depth, the chargeability response millisecond levels become stronger and begin to merge at about 150 meters in depth. As depth continues to increase, the chargeability star features ultimately merge to form the continuous chargeability anomalous area. The chargeability values in the Bolas anomaly reach their maximum (25 to 30 ms) at about 300 meters below surface and then begin to fade to around 20 to 25 ms at 500 meters.
Whipsaw Target Area
The most visible magnetic feature of the Whipsaw Target is a strong, broad, crescent-shaped magnetic high that fills more than half of the area. Inversion of the ground magnetic indicates that the deep-seated, crescent-shaped magnetic high is consistent with a deep-seated magnetic intrusive rock. A similarly intense, broad crescent-shaped magnetic high in the Copper Mountain area corresponds with mapped diorite intrusive rock and suggests that the magnetic high in the Whipsaw area may well be caused by the same rock type at depth.
The Whipsaw crescent-shaped, magnetic high partially surrounds a subcircular magnetic feature that is low, compared to the crescent-shaped high, but higher relative to magnetic background seen to the north. Once again, a similar pattern can be observed in the Copper Mountain area. There the subcircular magnetic feature corresponds with rocks mapped as monzonite and syenite, suggesting that the deep subcircular magnetic feature at Whipsaw may also be caused by a similar, less magnetic rock type. Strong chargeability anomalies occur within the subcircular magnetic feature.
Analysis of inverted resistivity data, with help from chargeability and magnetic inversions as well as magnetic intensity, indicates that the Princeton/Nicola contact may be vertical to sub-vertical and that the Princeton Group rocks could vary from about 150 to over 500 meters in depth, possibly over Nicola Group rocks. This may mean that the area of Princeton rocks could be down-dropped relative to the Nicola rocks across a fault-forming graben. If this is case, the deep moderate to weak chargeability anomalies seen in the area of Princeton rocks may then reflect the tops of chargeable material buried within Nicola rocks.