Sigma Lithium updates Grota do Cirilo feasibility, creates US$1.6B after-tax NPV

The updated economics demonstrate that Phase 1 is financially robust, even as a standalone
project and before factoring in a potential Phase 2 production expansion, Sigma said. The key factors influencing the study outcome include a high average mill feed grade of 1.55% lithium oxide (mineral reserve grade) and Phase 1 plant DMS (dense medium separation) process recoveries of 60.4%.

The updated Phase 1 capex is US$123.1 million, which is in line with expectations compared to the US$113.6 million estimated in 2019. Sigma remains fully funded to finalize construction of the commercial production plant.

The Phase 2 deposit has the potential for additional production of 220,000 tonnes per year or 33,000 tonnes lithium carbonate-equivalent (LCE), which is estimated to scale up the company’s total annual production to 450,000 tonnes per year (67,000 tonnes LCE) of battery-grade sustainable lithium.

The production expansion potential is based on an initial mineral reserve estimate of 21.8 million tonnes for the Phase 2 deposit and a 30% increase in the Phase 2 mineral resource, as well as additional DMS metallurgical test results that achieved lithium recoveries of approximately 60%.

In total, Sigma has increased its mineral resources to 58.9 million tonnes, including 50.4 million tonnes of measured and indicated resources at 1.40% lithium oxide. Total mineral reserves are estimated at 33.6 million tonnes, including 25.3 million tonnes of proven reserves at an average grade of 1.44% lithium oxide.

According to the company, Phase 2 construction of production plant foundation earth works could commence concurrent with the Phase 1 commissioning. An updated Phase 2 pre-feasibility study with combined Phase 1 and Phase 2 economics is expected in the second quarter of 2022.

For more information, visit www.sigmalithiumresources.com.