Pursuit Minerals (ASX:PUR) have released the results of its Controlled Source Audio Magneto Telluric (CSAMT) Geophysical surveys, conducted by Quantec Geosciences Argentina at its Rio Grande Sur Project in Salta, Argentina, identifying multiple zones considered highly prospective for lithium enriched brines.
The Rio Grande Sur Project covers five tenements of lithium prospective land across 9,233 hectares in Argentina.
Quantec began the CSAMT surveys in July this year, using an electromagnetic geophysical method applied for mapping subsurface resistivity, and were specifically designed to follow up on the recent Transient Electromagnetic (TEM) survey results, which revealed multiple zones highly prospective for lithium-enriched brines.
As the Company prepares for its inaugural drilling campaign to define a maiden JORC resource, the TEM survey highlighted layers of interest with low resistivity and high conductivity within the range of 150 metres to 300 metres, suggesting a promising path for future exploration and lithium brine expansion.
The Rio Grande Salar hosts an Inferred Resource of 2.1 million tonnes LCE at an average grade of 370mg/Li to a depth of 100 metres reported as part of an existing NI43-101 report, with Pursuit estimating 3000 hectares of its Rio Grande Sur tenements cover a section of this resource.
The Company reports the CSAMT surveys have furthered the existing TEM results, identifying interpreted brines to a depth of 500m, with planned drilling to this depth expected to significantly increase the resource.
The CSAMT survey technique allowed the identification of the lithologies associated with aquifers containing Lithium brine, as well as geological structures within the Mito tenement, reaching depths of up approximately 750 metres.
This forms valuable insights into the underground geology and hydrogeology of the tenement, particularly within the 500 metre range, which will be important in assisting with identification of the best drilling locations for the proposed campaign in 2024.
Figure 1: 3D rendering of low resistivity layer on the Mito tenement.
Geology of Mito
The CSAMT survey results helped determine the geology of the Mito tenement, with Pursuit reporting two distinct resistivity layers were identified including a large, deep and contiguous extremely low resistivity layer located from 200 metre depth to approximately 600 metres.
Upper High Resistivity Layer: The CSAMT survey determined a high resistivity layer of approximately 100 metres to 200 metres, with the presence of significant quantities of fresh water suggesting that the host lithologies are promising for future brine extraction.
Low Resistivity Layer: The CSAMT lines on the Mito tenement are uniformly characterised by a large, thick and contiguous extremely low resistivity layer located from 200 metre depth to approximately 600 metres. The low resistivity of these layers suggest it is porous and potentially host to high concentration brines.
After completing the CSAMT Survey, Pursuit now turns its attention toward the proposed Stage I forward works program for 2023 which consists of drilling four exploration drill holes, one for each of the Sal Rio I, Sal Rio II, Maria Magdelena and Isabel Segunda tenements in addition to a pumping well with the location to be decided at the time of the drilling campaign.
Furthermore, drill holes on the Mito tenement are planned for 2024 to test the potential for brine in the low resistivity layers identified from the CSAMT data, with actual locations and nominal depths to be confirmed and established prior to drilling.
Figure 2: Proposed drill hole location for Mito drilling campaign
Pursuit Managing Director and CEO Aaron Revelle said the CSAMT survey results confirm the Company’s assumptions about the Project.
“The results of the CSAMT survey have continued in line with our expectations that the Rio Grande Sur Project has potential to host a significant resource of Lithium brine which now extends to the Mito tenement,” he commented.
“The CSAMT data has outlined multiple low resistivity (high conductivity) layers from approximately 150 metres to 500 metres in depth at the Mito tenement. These layers are below the current Canadian National Instrument 43-101 (NI43-101) Inferred Resource drilling which extended to 100 metres.”
“The data additionally suggests that the area is conductive and could yield similar results to a company which drilled ~2 kilometres to the north-east of the Mito tenement off the Rio Grande Salar and yielded exceptionally high grades averaging 773mg/Li with several samples returning in excess of 850mg/Li from ~300m below the surface.”
PUR’s Australian Stock Exchange-listed share price is currently selling at $0.009 (11.00am UTC+ 8 hours).