The company had applied for a trial mining licence last month.
The PFS presented a two-phased approach, starting with a pilot plant able to produce 5,000 tonne of concentrate per annum, moving to a larger 25,000tpa plant in phase two.
The study put the capex for phase one at US$7.3 million and $27.2 million for phase two.
It outlined an after-tax NPV (5% discount) of $81.2M, an IRR of 35% and a 4-year payback, using a current average basket price of $1,287/t.
South Star reiterated both phases would use filtered tails technology and co-disposal of tailings with wasterock, to avoid the need for a tailings storage facility, an option it investigated last year in the wake of Vale's fatal Brumadinho dam collapse.
Pearce, who was appointed in mid-2019 for his mine-building and Brazil operating experience, said the pilot plant was expected to provide short-term cash flow and qualify bulk samples to establish offtake agreements.
He said the PFS highlighted a project with robust economics and was designed around a simple, proven flowsheet in one of the most prolific, high-quality graphite producing regions in the world.
"We will monitor closely the permitting and licensing process and will be using the first half of 2020 to get the financing in place to construct and commission the pilot plant facilities," he said.
"We are excited to be moving past project development and focusing all our efforts and attention on near-term construction, commissioning and production."
The company had working capital of about C$357,000 at September 30, having raised $405,000 at 10c per unit earlier in 2019.
Its shares shot up 25% - or 1c - yesterday to close at 5c, at the lower end of a 3-16c one-year range.
South Star is capitalised about $2.1 million (US$1.6 million).