Mission accomplished – KSM partner ready
Mining Explorers 2019 – Published Nov. 1, 2019
Last updated 8/14/2020 at 9:30am
With the four main deposit at KSM – Kerr, Sulphurets, Mitchell and Iron Cap – advanced to the feasibility stage, Seabridge Gold Inc. shifted the focus of its 2019 exploration on discovery targets beyond the vast copper-gold resources delineated so far across this property in British Columbia's Golden Triangle.
A prefeasibility study completed in 2016 detailed a mine for KSM that would produce an average of 540,000 oz gold, 156 million lb copper, 2.2 million oz silver, and 1.2 million lb molybdenum annually over a 53-year mine life.
At that time, the potential of Iron Cap was not fully understood, and this deposit wasn't slated to be mined until about 32 years into the life of a proposed operation for KSM.
Iron Cap, however, is closer to infrastructure than Kerr and Sulphurets and has the right geometry to consider being mined by block caving, a bulk underground mining technique. Due to these advantages, in 2017 and 2018 Seabridge focused on investigating whether the deposit had the size and grade to be considered for mining earlier in the mine plan.
This mission was a success, adding a million ounces of gold and billions of pounds of copper to Iron Cap since the completion of the PFS.
According to a resource calculated in March, Iron Cap hosts 423 million metric tons of indicated resource averaging 0.41 grams per metric ton (5.58 million oz) gold, 0.22 percent (2.05 billion lb) copper, 4.6 g/t (62.56 million oz) silver and 41 parts per million (38 million lb) molybdenum; plus 1.9 billion metric tons of inferred resource averaging 0.45 g/t (27.47 million oz) gold, 0.3 percent (12.56 billion lb) copper, 2.6 g/t (158.74 million oz) silver and 30 ppm (126 million lb) molybdenum.
With the Iron Cap expansion, KSM now has 2.98 billion metric tons of measured and indicated resources averaging 0.52 grams per metric ton (49.7 million ounces) gold, 0.21 percent (13.9 billion pounds) copper, 2.8 g/t (265 million oz) silver and 54 parts per million (312 million lb) molybdenum; plus 4.56 billion metric tons of inferred resource averaging 0.38 g/t (56.3 million oz) gold, 0.32 percent (32 billion lb) copper, 2.4 g/t (349 million oz) silver and 32 ppm (295 million lb) molybdenum.
With these resources in place, Seabridge has achieved its main KSM objective.
"Our first priority at KSM has been to ensure that the project is ready for final feasibility efforts when a partner is secured," said Seabridge Gold Chairman and CEO Rudi Fronk. "Now that this objective has been accomplished, we are intent on improving our understanding of the entire project and its district-scale potential by addressing the many opportunities that remain, using the extraordinary bank of knowledge we have accumulated over the past decade."
One such opportunity is high-grade gold occurrences on the margins of the Sulphurets deposit.
One hole drilled in this area last year, S-18-81, included a two-meter intercept averaging 1,580 g/t (50.8 oz/t) gold and 209 g/t silver. The next hole, S-18-82, cut 12.2 meters of 5.83 g/t gold and 7.2 g/t silver, and 3.95 meters of 18.5 g/t gold and 30.6 g/t silver.
These and other intersections are clustered within a northeast trending structure that extends for at least 800 meters along strike.
In late August, the company began a 4,000-meter drill program designed to further define this epithermal gold structure.
"Our original plans for this year at KSM were focused on completing geophysical surveys to help refine the limits of the existing four porphyry deposits and look for a fifth" said Seabridge Gold Chairman and CEO Rudi Fronk. "A concept to expand the 1500 g/t intersection drilled last year grew out of these surveys and the target was too compelling to ignore. This new target is within the proposed Sulphurets pit plan, so if the program is successful, we will immediately capture new resources."
Seabridge also continued to advance exploration at Iskut, a gold project about 30 kilometers (19 miles) west of KSM.
The company acquired Iskut and carried out its first drilling there in 2017. While this drilling cut several narrow, discontinuous intervals of high-grade gold it did not hit the mineralization sought. Further investigation revealed that much of the of the Quartz Rise lithocap had been eroded, leaving little opportunity for a sizeable high-grade epithermal occurrence in this area.
This more extensive than expected erosion coupled with geophysical evidence gave rise to another tantalizing possibility – a porphyry system that is much closer to the surface than previously envisioned.
This year, the company carried out deep penetrating geophysics to define potential drill targets at this potentially large porphyry target at Iskut.
Seabridge Gold's portfolio also includes the Courageous Lake gold property in Northwest Territories and Snowstorm gold property in Nevada.