The assays reported today from Golden Swan included 9.8m grading 4.95% nickel.
As well as a maiden resource estimate, Poseidon wants to make an investment decision on developing the deposit and other resources it has in the area by the end of 2021.
Golden Swan and Silver Swan are deposits north of Kalgoorlie adjacent to the Black Swan processing infrastructure.
Poseidon unveiled a A$22 million fundraising earlier this month to "drive progress" towards the start of operations at Black Swan.
The aim is to be back into production next year.
Poseidon shares were down 4.5% to 10.5c in afternoon trade, capitalising the company at $295 million.
The fundraising in train is pricing new shares at 11c each.
