Hombre Muerto North Lithium Project (HMN Li Project) in Salta Province, Argentina, is being developed by its 100% owner Lithium South (previously NRG Metals).

The company announced a Preliminary Economic Assessment (PEA) of the HMN Li project in 2019. The PEA estimated a 30-year mine life based on a production of 5,000 tonnes per annum (tpa) of lithium carbonate.

The Environmental Baseline Study (EBS) for the project was completed in March 2022. It was filed with the Mining Authority in May 2022.

In November 2023, Lithium South filed an Updated Mineral Resource Estimate which increased the lithium resource base in the project by 175%.

The company is advancing with a full feasibility study for the HMN Li Project.

Hombre Muerto North Project Location

The HMN Project is located in Salta Province, northwestern Argentina, around 380km from the city of Salta. It straddles the Salta and Catamarca Provinces in the southeastern Puna region.

Overall, the 5,687-hectare property comprises nine mining concessions, including six on the salar.

The six concessions are Alba Sabrina, Tramo, Natalia Maria, Gaston Enrique, Via Monte and Norma Edith.

The three additional properties, known as the Sophia properties, are located approximately 6km north of the Salar del Hombre Muerto (SHM) in Salta Province. The processing facility is anticipated to be constructed at the Sophia properties.

Notably, Korean company Pohang Iron and Steel Company (POSCO) is building a $4bn lithium project adjacent to Lithium South, while Allkem Livent with their new merger will develop the west and east portions of the salar.

Background Details of Hombre Muerto North Project

NRG Metals entered into an option agreement to purchase the HMN Li project in June 2017. Subsequent exploration work by the company was reported in the technical reports by Montgomery (2017; 2018) and KPC (2019).

In May 2019, NRG Metals formed a strategic alliance with US-based lithium extraction company Lilac Solutions to develop pilot project work for the HMN Li project.

Lilac had developed an ion exchange technology, called the IX Process, to address the challenges of conventional evaporative extraction of lithium from brines. According to Lilac, the process achieved 90% recovery of lithium from brine, which is double compared to evaporative technology.

In May 2021, Lithium South announced working with Eon Minerals, a Florida-based technology company, to evaluate the use of Direct Lithium Extraction (DLE) technology for its HMN Li project.

In October 2023, the first production well at the lithium brine project was installed.

In January 2024, Lithium South signed an agreement with POSCO Argentina to collaborate on the development of the HMN Li project.

Geology and Mineralisation

Salar del Hombre Muerto (SHM) is situated in the southern zone of the central Andean Puna-Altiplano plateau and features low-lying internally drained basins (salars).

The Alba Sabrina property includes a trending channel in the northwestern sector of the SHM, while the Natalia Maria property represents a halite-dominated area of the SHM.

Tramo is located in SHM’s clastic-dominated northeastern sector of the SHM.

Alba Sabrina, Natalia Maria, and Tramo properties’ brine resources are defined relative to a 500 mg/L lithium cut-off.

According to a project technical report published in 2023, the lithium grades and the levels of impurities in the project are regarded favourably against other brine deposits.

Hombre Muerto North Project Resources

In September 2023, Lithium South reported a 175% increase in the total lithium brine resources at HMN Li Project.

The resource base increased from 571,000 tonnes to 1.58 million tonnes (Mt) LCE at an average grade of 736 mg/L lithium with a low average magnesium (a brine contaminant) to lithium ratio of 3.27.

This includes in situ contained resources at the Alba Sabrina, Natalia Maria, and Tramo claim blocks.

Around 90% of resource is in the measured category.

Mining and Recovery

At Hombre Muerto North, well holes equipped with internal pumps will transfer brine to one of three pre-concentration ponds situated near the processing plant.

The PEA noted that nearly 100 L/s of brine will be required to feed the ponds and processing plant and produce 5,000 t/a of lithium carbonate (Li2CO3). It estimated that three well holes will enable it to achieve the rate, while additional holes will be drilled as a contingency measure.

The brine is a high-grade, low impurity brine – 736 milligrams lithium per litre. It contains a low magnesium to lithium ratio of 3.27 to one.

The recovery method involves lithium salar concentration and pre-purification through solar evaporation. This will be followed by advanced hydrometallurgical processing to purify the brine and recover Li2CO3.

The brine produced from the wells will be pre-concentrated through solar evaporation in shallow ponds. It will be followed by liming to remove bulk-impurities.

Subsequent chemical adjustment, solvent extraction and polishing precipitation will remove boron and advanced impurities.

Li2CO3 will be precipitated by carbonation with sodium carbonate and then purified by re-dissolution with carbon dioxide and re-precipitation by desorption.

Finally, the lithium carbonate will be dried, conditioned and packaged.

Key Infrastructure

A 600MW, 375kV power line connecting Salta and Mejillones in Chile passes about 160km north of the HMN Li property. A new line must be constructed to power the mining operations.

A natural gas pipeline also passes around 10km from the property area.

Freshwater required for the process plant operations will be provided by wells located approximately 3km away.

Offtake Agreement

In November 2017, Lithium South entered into a lithium off-take agreement with Chengdu Chemphys Chemical Industry. The off-take agreement gave Chengdu exclusive right of first offer (ROFO) to buy a portion or all lithium production from the HMN Li project.

Contractors Involved

Lithium South engaged Groundwater Insight to prepare an independent technical report for the lithium brine project.

Knight Piésold and JDS Energy & Mining prepared the Preliminary Economic Assessment Report for the Hombre Muerto North project.

The Environmental Baseline Study was completed by E&C Consultores.