The best intercept was 583m at 0.59g/t gold and 0.41% copper.
Seabridge said it had intersected some "exceptional widths of gold and copper mineralisation" with grades exceeding the KSM resource average.
Further results are expected within weeks to feed into a resource update in early 2019.
"Our expectation is to extend and improve our resource model for Iron Cap, which is on course to becoming one of the best deposits in the KSM complex," chairman and CEO Rudi Fronk said.
The company describes the shovel-ready KSM as the world's largest undeveloped copper/gold project by reserves, which currently total 2.2 billion tonnes at 0.55g/t gold and 0.21% copper, for 38.8 million ounces of gold and 10.2 billion pounds of copper, plus 183Moz of silver and 207Mlb of molybdenum.
A 2016 preliminary economic assessment put base case capex at US$5.5 billion with a pre-tax IRR of 12.7% and operating costs of negative $179/oz of gold over the 51-year mine life.
The company raised C$19.7 million (US$15.3 million) at a 27.1% premium of $17.16 per flow-through share in May to fund the KSM drilling programme.
Its shares closed up 2.34% yesterday to $17.07, near the middle of its 52-week range of $12.61-$19.84 and capitalising it over $1 billion.