Xuxa lithium project is an open-pit lithium deposit located in the Grota Do Cirilo Project in Vale do Jequitinhonha, Brazil. Sigma Lithium is the project owner and developer.
Sigma secured environmental licenses for the construction and installation of its lithium commercial production plant in June 2019.
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Feasibility study (PFS) for the Xuxa was completed in October 2019. It estimates an investment of £80.1m ($98.5m) to develop.
The Xuxa deposit is expected to produce 220,000 tons of high-quality battery-grade 6% lithium oxide concentrate a year, through its anticipated mine life of 9.2 years. The construction on the project is expected to be started in March 2020, with operations anticipated to begin in 2021.
Xuxa lithium project location, geology, and mineralisation
The Xuxa deposit is situated in Vale do Jequitinhonha in the northeastern state of Minas Gerais, Brazil. It is one of the six priority lithium deposits sites identified at Grota Do Cirilo. The mineralisation at Xuxa deposit comprises pegmatite that remains open on surface to the south and at depth.
The Xuxa pegmatite is approximately 1.7km-long and beween 14km and 16km in width. It dips roughly 50° west, striking north-west to south-east. The pegmatite is made up of large crystals of spodumene, which are clearly visible in the drill cores.
Ore reserves at Xuxa lithium project
The proven and probable ore reserves at Xuxa lithium deposit are estimated to be 13.79 million tonnes (Mt), grading 1.46% lithium oxide (Li2O).
The deposit is expected to contain measured and indicated resources of 17.41Mt and inferred resources of 3.8Mt.
Mining at Xuxa lithium project
Conventional open-pit mining method will be implemented at Xuxa lithium deposit, using a combination of hydraulic excavators and haul trucks. The mine plan involves the construction of two separate pits, in addition to four waste piles for storing the waste rock from open pits and residue from the Xuxa Plant.
The excavated material will be hauled to the run-of-mine (ROM) pad or the waste piles by trucks.
Controlled blasting will be used to maximise mine recovery and reduce dilution, with 6m benches used to blast fresh rock for ore domain and 12m benches for waste domain.
Ore processing at Xuxa lithium project
Ore will be processed at the 1.5Mtpa Xuxa processing plant, located 1.7km and 2.3km respectively from north and south Xuxa mine open-pits. The plant capacity is planned to be expanded to 3Mtpa by including an in-house crushing circuit.
The ROM ore will pass through a three-stage conventional crushing and screening circuit, followed by dense moderate separation (DMS) screening and mica removal. Coarse and fines will be processed in separate two-stage DMS circuits followed by a single-stage DMS circuit for ultra-fines fraction.
The resultant hypofines fraction with the waste will be thickened, filtered, and dry stacked. It will then undergo optical sorting and/or magnetic separation on the concentrate.
Off-take agreements
Sigma Lithium signed a heads of agreement, in November 2018, with Mistui for the off-take of the lithum produced at the Xuxa lithium project. The company paid £24m ($30m) for supplying 55,000t of battery-grade lithium concnetrate a year, for six years.
Infrastructure
The project will be powered by hydroelectricity, while approximately 90% of water used in the processing will be recycled.
Contractors involved
Sigma Lithium prepared the project feasibility study with support from consultants including SGS Geological Services, MCB (Dewsick Brazil), Primero Group, SGS Lakefield Canada, Primero Group Americas, and Worley Parsons.
