The Mariana Lake Project

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The Mariana Lake Project

The Mariana Lake Project consists of a lithium brine deposit located in Salta, Argentina. The region is known as the Lithium Triangle. The Lithium Triangle is host to lithium brine deposits that currently account for over 30% of the global lithium trade.

Salar de Llullaillaco, which makes up the Mariana project, is less than 140 km South of the Atacama Salar in Chile. Atacama is the largest producing lithium brine deposit in the world.

The Mariana project shares some characteristics with the brine operations in the Atacama Desert in Chile as both reside in the region known as the Puna. The Puna region has some of the lowest recorded precipitation and highest evaporation rates in the world making this an ideal place for an efficient natural solar concentration process.

The Mariana project has (base date November 2019) measured and indicated resource of 4,410,000 tonnes of LCE (Lithium Carbonate Equivalent) and an Inferred resource of 786,000 tonnes of LCE. This makes it one of the biggest lithium deposits in the world. Based on public sources as at February 2020 we believe Mariana is the fourth largest lithium exploration resource in Argentina and Chile after Cauchari-Olaroz, Olaroz, Cauchari, Hombre Muerto, but ahead of Pastos Grandes, Sal de Vida, 3Q and Maricunga. The project has access to rail infrastructure nearby which terminates at the port of Antofagasta in Chile, less than 300 kilometres away.

The Mariana joint venture owns 100% of the mineral rights (Minas) covering the entire Salar de Llullaillaco. There are no competing projects for brine resources within the entire basin giving the Mariana project an advantage over some other projects that share mineral rights over their salars.

On December 6, 2018, at at time that the indicated resource was still 1,300,000 tonnes following a 2017 survey, a preliminary economic assessment (PEA) for the Mariana Joint Venture was announced. The PEA technical report assessed the potential economic viability of developing the 14 exploration licenses (Minas), that cover the Salar de Llullaillaco (the Salar) and surrounding area (23,560 hectares), for the purpose of extraction of lithium brine resources and processing of two products – Lithium Carbonate Equivalent and Sulphate of Potash. It should be noted that this report was based on solar evaporation and shipping concentrated brine to China. It is now likely that, instead of this method, solvent extraction will be used. A revised PEA or feasibility study reflecting this improved process and the higher resource estimates is expected at the end of 2020. However until such time, the December 2018 report is the only report that can be relied on, and we also caution readers that for regulatory purposes a mineral resource is not the same as a reserve.

PEA Highlights**

Mine Life: 25 years


Lithium Carbonate Equivalent

Sulphate of Potash


10,000 tonnes per annum

84,000 tonnes per annum

CAPEX: US $243,000,000
NPV (after tax, 10% discount rate): US $192,000,000
IRR (after tax): 20%

The joint venture is between Ganfeng Lithium (GFL) and International Lithium (ILC) with ownership as at 1 May, 2020 divided as 87.209% to GFL and 12.791% ILC. ILC can acquire an additional 10% ownership through a back-in right.

Ganfeng Lithium is one of the largest lithium product manufacturers in the world and is working to become a fully integrated lithium and lithium battery supply company.


The Mariana project is located close to the border of Chile along the Salta–Antofagasta Railway. The area surrounding the Mariana project is a well-established mining district with the Taca Taca copper project and the Lindero gold project close by. The Escondido copper mine is also close by on the Chilean side of the border.

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The Mariana project is serviced by all-weather roads and is in close proximity to the existing Salta – Antofagasta rail line.


Salar de Llullaillaco

The Salar de Llullaillaco which makes up the Mariana Project is approximately 16 kilometres in the North-South direction and 10 kilometres in the East-West giving over 160 square kilometres (16,000 hectares) of prospective resource.


Drilling and Resource Definition

Drill hole location map.

Pump well location map.



Gravity surveys helped to identify the basement of the Llullaillaco basin as seen here in the Bouguer gravity anomaly map. The area used in calculating the Maiden resource is indicated by the dashed blue line.

Electromagnetic (EM) surveys help to define the rich brine aquifers.

3D representation of resistivity from the EM surveys

Cross section from EM survey showing interpreted aquifers and geologic units.


Process Studies

Brine concentration through natural solar evaporation.

The current focus on lithium recovery studies is on using natural solar energy to concentrate the lithium in the brine through evaporation. This is currently being tested on-site using a series of evaporation ponds. An on-site laboratory is used to analyse the chemical changes in the brine in a timely manner.


Resource Estimate

Indicated resource*:  1,248,000 tonnes of LCE (Lithium Carbonate Equivalent)

Inferred resource*:  618,000 tonnes of LCE

  • The indicated resource is estimated at 765 billion litres of brine grading:

  306 mg/L lithium (Li)
  9,457 mg/L potassium (K)

  • The inferred resource is estimated at 361 billion litres of brine grading:

  322 mg/L lithium (Li)
  10,316 mg/L potassium (K)

  • Brine resources are tabulated and reported for average specific yield (SY) of 15% and a cut-off value of 230 mg/L Li. Effective date for this resource estimate is January 20, 2017

* Technical Report; Mariana Lithium Project, Salar de Llullaillaco, Argentina”, April 10, 2017 (, authored by Geos Minerals Consultants. The effective date for the resource estimate is January 20, 2017, which represents the date of the most recent data that supports the brine estimate in the Technical Report.

Tabulated Resourse Estimated Figures.

Category Effective Volume Brine Density Li B K Li LCE
  Mm3 g/mL mg/L mg/L mg/L Kt Kt
Indicated 766 1.218 306 599 9,456 234 1,248
Inferred 361 1.222 322 642 10,316 116 618


Preliminary Economic Analysis (PEA) Highlights **

  • 25-year mine life producing 10,000 tonnes per year (“TPY”) Lithium Carbonate Equivalent (“LCE”) plus 84,000 TPY Sulphate of Potash (“SOP”).
  • The estimated CAPEX and OPEX are for a conventional brine extraction facility, solar evaporation ponds and SOP processing with a level of accuracy of -30/+50%.
  • CAPEX estimated at US $243 million for 25-year mine life.
  • NPV = US $192 million after-tax at 10% discount rate, IRR = 20% post-tax.
  • Project results remain positive, even with important negative variations on the driver variables, indicating project strength and resilience; thus, the PEA study indicates Mariana’s proposed 10,000 TPY LCE concentrated brine and 84,000 TPY SOP fertilizer operation has the potential to generate strong economic returns.

** The PEA was prepared by Advisian (“Advisian”), a division of the WorleyParsons Group, for Mariana Lithium Corp. to provide a PEA of its Mariana Lithium Brine Project in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”). The PEA technical report assesses the potential economic viability of developing the 14 exploration licenses (Minas), that cover the Salar de Llullaillaco (the Salar) and surrounding area (23,560 hectares), for the purpose of extraction of lithium brine resources and processing of two products – Lithium Carbonate Equivalent and Sulphate of Potash. All figures are quoted in US dollars. It should be noted that the Company did not play any significant part in the production of the PEA report, and that the conclusions are therefore those of the consultants.

Cautionary Note:
The preliminary economic assessment (PEA) is preliminary in nature, and it includes inferred mineral resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves, and there is no certainty that the preliminary economic assessment will be realized. The PEA includes the results of an economic analysis of mineral resources, and mineral resources that are not mineral reserves do not have demonstrated economic viability.