This 2011 Preliminary Economic Assessment describes a proposed lithium brine project in Salta, Argentina, with conceptual processing based on solar evaporation and off-site chemical conversion.
Report context
This NI 43-101 Technical Report and Preliminary Economic Assessment for the Salar de Diablillos Project, Salta, Argentina, is dated December 22, 2011, with an effective date of November 8, 2011. The report was prepared for Rodinia Lithium, Inc. The project is a brine deposit characterized by elevated lithium, potash and boron, hosted in a high-altitude evaporitic basin in the Puna region of northwest Argentina, approximately 145 km southwest of the city of Salta.
Processing route
Proposed process overview
The proposed lithium recovery process is a combination of solar evaporation steps, in-field brine treatment, by-product boric acid and sylvinite recovery, and chemical processing to produce lithium carbonate. Rodinia anticipates construction of various solar and process ponds at the salar with production of sylvinite as a saleable product.
On-site process components
The on-site process at Salar de Diablillos comprises a brine wellfield, solar pond, settling pond, halite ponds, and sylvinite ponds. The base case development scenario includes an average yearly production of 15,000 t-LCE, 52,000 t-potash and 18,000 t-boric acid.
Concentrated brine, or bittern, will be transported approximately 130 km via truck and tanker equipment to a new lithium carbonate and boric acid recovery facility located in Pocitos, Salta Province. This off-site process is where the bittern will be processed for recovery of lithium carbonate and a boric acid product.
Off-site process components
The off-site process facility at Pocitos includes a boric acid recovery facility and a lithium carbonate plant. Rodinia plans to access a land parcel in a designated industrial park at Pocitos. The plant site has access to fresh water for chemical processing and natural gas for power generation. The industrial park is adjacent to a main highway for raw material and product transportation and also adjacent to high tension power lines that may be accessed in the future.
Testwork status
As of the date of this Technical Report, there has not been on-site mineral processing test work related to bittern production or lithium carbonate recovery. Rodinia recognizes that the process flow sheet needs to be verified by in situ pilot ponds at the salar as well as the collection of weather data. Weather data such as evaporation rates affects the sizing of the ponds as well as the chemistry. All may be affected due to ambient temperature.
In 2012, Rodinia intends to construct a pilot-scale series of evaporation ponds to produce bittern. The lithium-bearing bittern product will then be subject to additional testwork to confirm the process flow sheet for production of lithium carbonate and boric acid. Rodinia also intends to isolate the potash-bearing solids (e.g., sylvinite) and confirm the process flow sheet for production of potash.
Hydrogeological modeling
Based on field hydrogeologic test work conducted between July and October 2011, SRK completed numerical modeling of the Salar de Diablillos aquifer system using MODFLOW-2005 and MT3DMS finite-difference codes. The brine extraction model indicates that brine extraction to produce 15,000 tpa of lithium carbonate during a 20 year period is not limited by hydrogeological or hydrogeochemical parameters of the Salar de Diablillos. Extraction of brines to meet a production target of 25,000 tpa of lithium carbonate during a 20 year period may be possible but might be limited to some extent by hydrogeological and hydrogeochemical parameters, which require further characterization.
Product specifications
The proposed beneficiation process estimates that the lithium carbonate product would have 19.8% content of lithium, corresponding to a purity of 99.9% lithium carbonate equivalent. Studies of the Potash flotation plant indicate an output product with 50% contained potassium, corresponding to 95% purity when compared to potassium carbonate.
Key reported parameters
| Parameter | Value | Basis |
|---|---|---|
| Average LCE production (yearly) | 15,000 t | Base case design |
| Average Potash production (yearly) | 52,000 t | Base case design |
| Average Boric acid production (yearly) | 18,000 t | Base case design |
| LCE product purity | 99.9% (19.8% Li) | Design/product specification |
| Potash product purity | 95% (50% K) | Design/product specification |
| Brine transport distance | ~130 km (truck/tanker) | Proposed logistics |
| LCE average sales price | US$5,500/t | Assumption used in PEA |
| Potash average sales price | US$620/t | Assumption used in PEA |
| Boric acid average sales price | US$1,150/t | Assumption used in PEA |
| Average operating cost (LCE) | US$2,280/t-LCE | Estimated, excluding royalties and freight |
| Initial capital cost (total) | US$119.7M | Conceptual estimate |
| Contingency (20%) | US$23.9M | Conceptual estimate |
| Pre-production period | 3 years | Assumption |
| LCE production target sustainability (15,000 tpa) | 20 years | Hydrogeological modeling indicates not limited |
| LCE production target sustainability (25,000 tpa) | May be possible | Sensitivity case, requires further characterization |
Project website: http://rodinialithium.com/lithium_project/diabillos/
Technical qualifications
Significant risks and uncertainties noted in the report include:
- The status of the surface rights was not confirmed by the QPs; surface rights will be required to support a Feasibility Study.
- For the brine resource estimate, specific yield values were assumed based on data from analogous salars in the region with similar porosity and stratigraphy.
- There have been no engineering studies performed; preliminary exploitation concepts include extracting the brines through pumping wells and surface trenches.
- Rodinia has not secured a land parcel in Pocitos for the off-site LC plant and boric acid circuit, nor access to natural gas or process water supply in Pocitos.
- Rodinia has not secured transportation arrangements for rail and truck shipment of LC, potash or boric acid to market.
- Reagent pricing in northwest Argentina is uncertain.
- Given the elevation of the salar (4,000 m), the variation of diurnal temperatures will have a serious effect on the crystallization of compounds as well as changing the dynamics of the phase diagram. Only after piloting the evaporation sequence will the process be defined.
- There has not been on-site mineral processing test work related to bittern production or lithium carbonate recovery as of the report date.
- The prediction of the in-situ recoverable resource quantity, the method of brine extraction and the performance of the process flow sheet is subject to uncertainty that is not common to traditional hard rock projects, including 3D variability of effective porosity, specific yield and hydraulic conductivity; numerical modeling reliance on accurate physical parameter estimation; potential fresh water inflow or layering; and resource re-distribution during production.
Source: Salar de Diablillos Project , 2011 Technical Report, NI 43-101 Technical Report, Preliminary Economic Assessment, Rodinia Lithium, Inc., Report Date December 22, 2011, Effective Date November 8, 2011. Relevant sections: Summary, Sections 11, 13, 14, 16, 17, and Recommendations.
