The subsequent scoping study showed the mine also had potential for downstream processing.
The modified PFS is expected to be ready by the first quarter of 2021.
Capital costs over the life of mine will top $129 million.
Probable ore reserve updated to 253 million tonnes at 0.35% copper and 0.32% nickel.
The PFS showed Jervois would give strong financial returns.
The PFS also includes an updated mineral resource estimate over eight of the project's 24 lakes.
Richmond-Julia Creek is to be a shallow open pit operation with a 20 year mine life.
CZR set to finish Robe Mesa PFS in December, the company says.
Work on the PFS started in late July, with the results expected to be delivered in January.
According to the study the mines could deliver 63,000 ounces a year for six years.
Part of a regional province, Robe Mesa is next to two Rio Tinto mines.
The simplified design increases overall recovery and reduces the amount to be processed.