Enormous open pit mines emerging at KSM
Drilling indicates easy integration of Snowfield into mine plan North of 60 Mining News – November 5, 2021
Last updated 11/12/2021 at 7:02am
Early results from the 2021 drill program at KSM project support Seabridge Gold Inc.'s concept of mining more gold-rich reserves from open pits at the Snowfield and Mitchell deposits prior to the start of underground block cave mining at this world-class gold-silver-copper project in British Columbia's Golden Triangle.
Lying immediately east of Mitchell, one of four deposits on Seabridge's KSM property, Snowfield hosts 1.37 billion metric tons of measured and indicated resources averaging 0.59 grams per metric ton (25.92 million oz) gold, 1.72 g/t (75.8 million oz) silver, 0.1% (2.98 billion pounds) copper, 85.5 parts per million (258.3 million lb) molybdenum, and 0.51 ppm (22.5 million oz) rhenium.
In a deal that closed late last year, Seabridge acquired this large project on the east border of the KSM property from Pretium Resources Inc. for US$100 million, plus a contingent payment of US$20 million that would be paid within six months of commercial production from Snowfield or a bankable feasibility study for the property.
World-class in its own right, the Snowfield resource is only about half the size of KSM.
Four deposits at KSM – Kerr, Sulphurets, Mitchell, and Iron Cap – host 2.98 billion metric tons of measured and indicated resources averaging 0.52 g/t (49.7 million oz) gold, 0.21% (13.9 billion lb) copper, 2.8 g/t (265 million oz) silver and 54 ppm (312 million lb) molybdenum.
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.
The largest portion of the KSM resources considered in this PFS is found at Mitchell, which hosts 1.8 million metric tons of measured and indicated resources averaging 0.59 g/t (34.3 million oz) gold, 0.17% (6.6 billion lb) copper, 3.1 g/t (179 million oz) silver, and 58 ppm (230 million lb) molybdenum.
This means that the Snowfield and Mitchell deposits host a combined 60.2 million oz gold, 9.6 billion lb copper, 255 million oz silver, and 488 million lb of molybdenum.
A 9,450-meter drill program carried out this year at KSM included 3,484 meters of drilling to confirm model grades and carry out metallurgical testing of the material from these adjacent open-pit mineable deposits.
"The critical objective for our 2021 drill program at KSM was to enable us to merge our 2020 Snowfield acquisition into the greater KSM project," said Seabridge Chairman and CEO Rudi Fronk. "Both the Mitchell and Snowfield resource models are holding up very well."
Highlights from the drilling include:
• 417 meters averaging 0.71 g/t gold, 0.18% copper, and 3 g/t silver from a depth of 33 meters in hole M-21-150 drilled at Mitchell.
• 444.5 meters averaging 0.89 g/t gold, 0.25% copper, and 5.1 g/t silver from a depth of 5.5 meters in hole M-21-151 drilled at Mitchell.
• 430.9 meters averaging 1.08 g/t gold, 0.19% copper, and 2.2 g/t gold from a depth of 4.1 meters in hole SF-21-05 drilled at Snowfield.
"We foresee a seamless integration of Snowfield into KSM by blending Snowfield ore with Mitchell production, resulting in a meaningful extension of open pit mining prior to any underground block-cave mining," said Fronk.
Assays are in progress for the additional drill holes, primarily in the Snowfield deposit, including geotechnical drilling at the margins for pit slope determination, which are crucial to finalizing a resource update.
A new KSM preliminary feasibility study, which is expected to significantly increase KSM reserves by incorporating Snowfield in the mine plan, is scheduled for completion by mid-2022.
"We are increasingly confident that integration of Snowfield into a new KSM mine plan will increase proven and probable gold reserves, increase grades in the early years of production and defer the need to pay for expensive underground block-cave development," said Fronk. "These expected gains, along with higher metal prices, will help offset the impact of inflation on materials and labor costs and we believe will improve project economics."
The 2021 KSM drilling also included holes to evaluate the geotechnical characteristics along the planned Mitchell-Treaty tunnel (MTT), which is a critical piece of the infrastructure that would be used to haul ore to the mill for KSM.
CORRECTION: The opening sentence of this article was corrected to say early results from the 2021 drill program at KSM project support Seabridge Gold Inc.'s concept of mining more gold-rich reserves from open pits at the Snowfield and Mitchell deposits