The Hombre Muerto North project is a high-grade lithium project located north of Hombre Muerto Salar, Salta Province, Argentina. NRG Metals is developing the project with an estimated capital expenditure of $93m.
The preliminary economic assessment (PEA) of the Hombre Muerto Norte project was completed in April 2018. First production is anticipated to be made in 2021 and expected to increase in 2024. The mine is estimated to have a life of 30 years.
Production from the mine during the first two years is anticipated to be 3,750 tonnes per annum (tpa) and 4,500tpa respectively of lithium carbonate equivalent (LCE). The mine is expected to produce 5,000tpa of LCE from the third year of production until the end of mine life.
Hombre Muerto North project location, geology, and mineralisation
In May 2017, NRG Metals entered a purchase option to acquire the lithium project from One Borax, which is owned by a private borate producer Mr Jorge Moreno.
The property extends over 3,287ha and comprises six concessions namely Alba Sabrina, Tramo, Natalia Maria, Gaston Enrique, Viamonte, and Norma Edit.
The Salar del Hombre Muerto basin comprises a sequence of schists and migmatites mixed with metamorphic limestone and amphibolites.
The project area comprises three geological units namely Cordon del Gallego Range, Farallón Catal Range, and the Peninsula Tincalayu.
The Hombre Muerto lithium basin comprises a halite-dominated evaporite core, with steep and fault-controlled basin margins.
The Tramo concession of the Hombre Muerto North project is estimated to contain measured and indicated mineral resources of 142 million cubic metres (m³) of brine. It is estimated to contain 570,979t of Li2CO3 equivalent and 1.84 million tonnes (Mt) of KCl-equivalent.
Mining and processing
The mine design includes the construction of four wells in the Tramo property, of which three will be used for production and one well will act as a back-up.
Brine will be extracted from two well holes (TWW 18-01 and TWW 18-02), drilled near each core hole. The extraction wells are proposed to be accessed through a 4.5km road, built with compacted granular fill. With a diameter of 200mm each, high-density polyethylene pipes will be installed along the road to connect the three brine wells with the concentration ponds.
The project will use the ion exchange technology IX Process, developed by Lilac Solutions, to produce concentrated high-purity lithium solutions in a shorter period. NRG Metals and Lilac signed a strategic alliance agreement for the project in May 2019.
The recovered brine will be pre-concentrated through solar evaporation in shallow ponds, followed by bulk impurity removal using lime. The resultant product will be concentrated through solar evaporation, chemical adjustment and boron removal by solvent extraction.
Polishing precipitation process will be applied to remove any impurities present in the concentrated product.
The resultant lithium carbonate will be precipitated by carbonation with sodium carbonate (Na2CO3) to produce technical-grade product (99% Li2CO3). The product will be subject to purification and re-precipitation processes to produce a high-purity lithium carbonate (Li2CO3) product. The resultant product will be dried, conditioned, and packaged.
The project can be reached from the city of Salta, along national route RN-51 for 230km to Cauchari while traversing the towns of Campo Quijano and San Antonio de Los Cobres.
Liquefied natural gas (LNG)-powered generators will supply the required power for the operations. A 1.5MW solar power plant will also be available to provide back-up power.
Freshwater wells located approximately 3km from the site will be the source of non-potable water required for the mill and other industrial uses. Potable water will be brought in bottles for consumption by workers in the offices and camp.
The LNG required for the project will be provided by a subcontractor, who is also responsible for providing the tanks to store the gas on-site.
Workers will be accommodated at a 65-person camp to be located near the industrial complex.
Lithium offtake agreements
NRG Metals and NRG Metals Argentina entered a lithium offtake agreement with Chengdu Chemphys Chemical Industry (Chengdu) in November 2017 for the sale of lithium products from the project.
Chengdu secured the right of first offer (ROFO) to buy any or all production of lithium products from the project through the agreement.
NRG Metals engaged Wichi Toledo as the drilling contractor for the project while AGV Falcon Drilling was awarded the initial drilling contract.
Knight Piésold and JDS Energy & Mining prepared the National Instrument 43-101 Technical Report of the project.