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Seabridge has narrowed targets below Quartz Rise lithocap North of 60 Mining News – May 22, 2020
2018 drilling at Iskut tested for a near surface epithermal precious metals system at Quartz Rise. This year's program is seeking a deeper bulk-tonnage porphyry copper-gold target.
Seabridge Gold Inc. May 19 announced plans for a roughly 8,000-meter drill program to test for a gold-copper porphyry deposit at its Iskut project in British Columbia's Golden Triangle similar to those on the company's nearby KSM property.
"We acquired Iskut because we saw clear evidence of a large porphyry system which looked to be similar in age and geology to our KSM project 30 kilometers to the east," said Seabridge Gold Chairman and CEO Rudi Fronk.
Three years of work at Quartz Rise including two small drill campaigns have isolated a promising source of the Quartz Rise lithocap above the historic high-grade Johnny Mountain gold-silver-copper mine. Lithocaps are typically formed above a deeper porphyry system, which is the larger gold-copper deposit Seabridge is seeking at Iskut.
Previous drilling at Quartz Rise focused on testing for high-grade epithermal precious metal occurrences associated with the uppermost portion of a porphyry mineral system. Results determined that the lithocap that would have hosted these occurrences had been extensively eroded, exposing the upper part of a porphyry system. Porphyry-style vein fragments identified in 2018 confirmed an underlying porphyry source for the lithocap.
In order to refine targets for the underlying porphyry intrusive system that would account for the mineralization found at Quartz Rise, the 2019 program at Iskut included three dimensional induced polarization (IP) and high resolution magnetic geophysical surveys, as well as the collection of 184 surface geochemical samples.
This work expanded the geophysical footprint of the Quartz Rise porphyry target to the south and southwest into an area where glacial erosion exposed the system vertically over at least 800 meters, making it an easy target to drill from the surface.
Mapping and sampling of this vertical exposure found extensive gold and copper anomalies within favorable thermally-altered wall rock. Several intrusions were identified which have been dated to about 187 million years, the same age as the KSM deposits.
This year's initial 8,000-meter drill program at Iskut will evaluate about 750 meters of strike and 800 meters of vertical projection on coincident magnetic and IP anomalies that are below and west of the well-developed lithocap. The plan is to drill across the IP anomaly and a distinct magnetic feature which encloses a diatreme encountered in previous drilling. The diatreme contained abundant fragments of vein material indicative of the potassic core to a gold-copper porphyry system.
Seabridge had success testing a similar pattern of magnetic and resistivity anomalies at KSM, leading to the discovery of Deep Kerr, a deep zone on the world-class property with 1.9 billion metric tons of inferred resource averaging 0.31 grams per metric ton gold and 0.41% copper.
Rigorous procedures have been established to minimize the risks associated with COVID-19 during this summer's drill program, which is expected to begin in June.
"We are now working with the Tahltan Nation, B.C. Regulators, our suppliers, and consulting with competitors to advance our target this season in a manner that will ensure safe operations during the COVID-19 pandemic," Fronk said.
Over his more than 16 years of covering mining and mineral exploration, Shane has become renowned for his ability to report on the sector in a way that is technically sound enough to inform industry insiders while being easy to understand by a wider audience.
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