An updated resource estimate for Sigma Lithium Resources Corp.'s Grota do Cirilo lithium project in Brazil defined measured and indicated resources of 45.7 million tonnes grading 1.38% lithium oxide, a 254% increase in tonnage as compared to the estimate included in a March 2018 technical report.
Inferred resources increased 992% to 6.6 million tonnes grading 1.34% Li2O. The analysis, which covers the Xuxa, Barreiro, Murial and Lavra do Meio deposits, used a cutoff of 0.5% Li2O.
The company said Jan. 10 that the estimate represents 1.6 million tonnes of lithium carbonate equivalent in the measured and indicated categories, with 220,070 tonnes of LCE classified as inferred.
Sigma Lithium expects to complete a definitive feasibility study for the Xuxa deposit by the end of April. If it lines up with company expectations, Sigma Lithium will assess an annual production rate of 240,000 tonnes of battery-grade spodumene concentrate.
The company plans to subsequently conduct a feasibility study on the Barreiro deposit as a first step in targeting an increase in production capacity to 440,000 tonnes per year, based on the increased resource base at the project.
Sigma Lithium's development efforts in 2019 will include a third drill campaign focused on seven remaining priority targets and additional drilling of the Barreiro and Murial deposits.
The company also outlined various staffing changes. Independent director Maryse Belanger will become nonexecutive vice chairman. Belanger replaces Ana Cabral-Gardner in the role; Cabral-Gardner is joining the senior management team as chief strategy officer and an executive director.
Marcelo Freire de Paiva was added to the company's board of directors, while Tadeu Carneiro resigned from the board for personal reasons.
Cabral-Gardner and Paiva are co-founders and managing partners of A10 Investimentos Ltda., which owns 72.41% of Sigma Lithium.