The company announced an updated resource for Iron Cap yesterday, increasing the indicated resource by 0.46 million ounces of gold and 177 million pounds of copper, to 423 million tonnes at 0.41g/t gold and 0.22% copper for 5.58Moz and 2 billion pounds of copper.

The inferred resource increased by 7.45Moz of gold and 4Blb of copper compared with the 2018 estimate, to 1.9Bt at 0.45g/t gold and 0.3% copper for 27.47Moz of gold and 12.5Blb respectively.

The indicated molybdenum resource dropped from 39Mlb to 38Mlb but the inferred grew from 34Mlb to 126Mlb; while the silver resources increased to 62.6Moz indicated and 158.7Moz inferred.

Seabridge chairman and CEO Rudi Fronk said the new resource estimate achieved the targeted size and grade likely to warrant moving Iron Cap ahead of the Kerr and Sulphurets deposits in the mine plan for KSM, billed as one of the world's largest undeveloped copper-gold projects.

"Iron Cap is closer to infrastructure than Kerr and Sulphurets and its development could be faster and less costly," he said.

"Within the 1.9 billion tonnes of inferred resource, there exist significantly higher grade underground cave opportunities with substantial tonnage.

"Iron Cap clearly has the size and grade to justify early inclusion in the mining sequence.

"From our point of view, this is mission accomplished."

Iron Cap was treated as a potential block cave mining target and the estimate was calculated using a C$16 NSR cut-off.

A 2016 preliminary economic assessment for KSM had outlined negative operating costs of -$179/oz of gold over the life of mine and put base case capex at US$5.5 billion for the 51-year project.

Seabridge is also exploring for a KSM-style porphyry system at its Iskut project 30km away.

The company raised C$14 million (US$10.5 million) at $14 per share in November for its Snowstorm gold project in Nevada and gained a further $3.5 million through the exercise of options in December.

It had reported cash and short-term deposits of $10.5 million (US$7.8 million) at the end of September.

Seabridge filed a preliminary shelf prospectus in January to allow it to raise up to $100 million (US$75 million), but Fronk noted the company currently had no plans to arrange additional financing and said the dollar amount did not reflect an estimate of future requirements, which would depend on future developments and opportunities "which are unknowable at this time".

Seabridge shares have risen from about $13 a year ago to a 52-week high last month of $20.10.

They closed up 12c to $18.70 yesterday to capitalise it at $1.15 billion.