In a paper published in the journal Earth's Future, scientists point out that previous studies have not addressed two important factors which has led to misguided estimations and assumptions.
The 25%-ready Grota do Cirilo lithium project will not be constrained by quotas so Sigma will mine the north and south pits simultaneously.
It's the latest attack against a wave of new technologies aiming to produce the electric vehicle battery metal.
The Zulu lithium mine is expected to produce 48,000 tonnes of spodumene concentrate a year.
Privately owned Lithea owns rights to two lithium salt lakes in Argentina's mineral-rich Salta province.
Separately, Vulcan said it had received a positive result for its preliminary environmental impact assessment application in Germany.
The Caribbean country has set up a special senate committee to investigate how best to commercialize and develop potential lithium resources.
Sigma's Brazilian unit expects to start producing lithium by the end of the year.
The share sale breaks a months-long drought for large offerings in Hong Kong.
The miner lost more than a third of its value on Wednesday as it also announced the immediate departure of its CEO.