Lithium Argentina Expands Cauchari-Olaroz Resource Estimate; Supports Stage 2 Development Plan

Original announcement by tmx on

Company
Lithium Argentina AG
Ticker
LAR
Exchange
TSX
Region
Jujuy Province, Argentina
Primary commodity
Lithium
Secondary commodities
None reported
Document categories
Resource update, Other
Extracted
2026-09-18 06:53:02 UTC

Analysis by Minestarters Atlas

Minestarters Atlas analysis

Summary

Lithium Argentina has updated its Cauchari-Olaroz resource and reserve estimates, significantly expanding the Measured and Indicated lithium resource by 42% to 28.1 Mt LCE. While total reserves decreased by 28% to align with the Stage 1 production capacity of 40,000 tpa, the update incorporates new drilling and improved hydrological modeling to support Stage 2 development.

Reasoning: The announcement reports a substantial expansion of the lithium resource base (M&I up 42%) driven by new drilling and improved hydrological modeling, though total reserves are lower as they are now constrained to the Stage 1 production profile.

Positive factors

  • Significant M&I resource growth (42%)
  • Measured resource expansion (367%)
  • Inferred resource expansion (104%)
  • Incorporation of production data and hydrological modeling
  • Reserve model aligns with Stage 1 production

Negative factors

  • Total P&P reserves decreased by 28% due to alignment with Stage 1 capacity

Facts used in scoring: 5

Classification and evidence

Tonnage Growthpositive

Tonnage increase reaching the strong tier vs prior estimate, with grade maintained or improved.

Why it applies: Total M&I LCE resource increased by 42% compared to the 2019 estimate.

Evidence · text

“Increased Measured and Indicated (“M&I”) resource estimate by 42% to 28.1 Mt of LCE”

Category Upgradepositive

Resource confidence improved — Inferred upgraded to Indicated, or Indicated to Measured. De-risking signal.

Why it applies: Measured resource LCE increased from 3.6 Mt to 16.8 Mt.

Evidence · table

“16.8”

Context: 3.6

QP/CP Signedpositive

Qualified Person (QP) or Competent Person (CP) named and signed off — a member of a recognized professional association (e.g., AusIMM, SME, AIG, P.Geo) with relevant experience.

Why it applies: Mark King, PhD. PGeo, FGC is named as the independent Qualified Person for the 2026 estimate.

Evidence · text

“The independent Qualified Person for the 2026 Mineral Resource Estimate is Mark King, PhD. PGeo, FGC.”

NI 43-101 Compliantpositive

Resource estimate prepared in compliance with NI 43-101 (Canada) — high reporting standard.

Why it applies: The company states the estimate is prepared in accordance with NI 43-101 and CIM guidelines.

Evidence · text

“in accordance with the guidelines for lithium brines set forth by the Canadian Institute of Mining, Metallurgy, and Petroleum (CIM 2012), National Instrument 43-101”

Cut-off Disclosedpositive

Cut-off grade used for resource reporting is clearly stated, enabling like-for-like comparison.

Why it applies: A lithium grade cutoff of 300 mg/L is explicitly stated.

Evidence · text

“A lithium grade cutoff of 300 mg/L is used to define the Mineral Resource Estimates in both 2019 and 2026.”

Tonnage Declinenegative

Resource tonnage decreased vs prior estimate — pit optimization removed marginal material or geological model revised down.

Why it applies: Total Proven and Probable reserves decreased by approximately 28% compared to the 2019 estimate.

Evidence · text

“Total Proven and Probable reserves decreased by approximately 28%”

Resource Updateneutral

Revised estimate for an existing resource — compare to prior to assess progress.

Why it applies: The source explicitly discloses a revised resource estimate

Evidence · text

“increased resource”

Extracted facts

Stored fact records: 5. Some facts used in scoring do not have a stored record.

Resource Estimates (5)

measuredCauchari-Olaroz · lithiumTonnes: 16844844Grade: 557Grade Unit: mg/LContained Metal: 16844844Contained Unit: tView all details
Link to this fact

Identity

Project
Cauchari-Olaroz
Commodity
lithium
Region
argentina
Reported Region
Jujuy Province, Argentina
Ticker
LAR

Resource scope

Estimate type
resource
Effective date
2025-12-31T00:00:00.000Z
Reporting standards
ni_43_101
QP Signed
Yes
Qualified person names
Mark King
Resource group id
resource:96258b25720d4a5ef0b7
Ownership percent
44.8 %

Resource Data

Category
measured
Tonnes
16844844
Grade
557
Grade Unit
mg/L
Contained Metal
16844844
Contained Unit
t
Cutoff Grade
300
Cutoff Unit
mg/L

Prior Estimate

Resource Date
2025-12-31

Review

Needs Review
No
Historical
No

Dates

Event date
2026-03-11T00:00:00.000Z

Reasoning: Significant increase in measured resource tonnage and grade confidence.

Positive factors

  • Massive expansion of measured category

Evidence · table

“16,844,844”

Context: 5.94E+ 10

Tags used in scoring

Measured Resourcepositive

Highest confidence category — tonnage, grade, shape well-established from closely-spaced drilling. Basis for Proven Reserves.

Why it applies: category is "measured"

Cut-off Disclosedpositive

Cut-off grade used for resource reporting is clearly stated, enabling like-for-like comparison.

Why it applies: cutoff_grade is stated

QP/CP Signedpositive

Qualified Person (QP) or Competent Person (CP) named and signed off — a member of a recognized professional association (e.g., AusIMM, SME, AIG, P.Geo) with relevant experience.

Why it applies: qp_signed is true

NI 43-101 Compliantpositive

Resource estimate prepared in compliance with NI 43-101 (Canada) — high reporting standard.

Why it applies: reporting_standards includes ni_43_101

Resource Updateneutral

Revised estimate for an existing resource — compare to prior to assess progress.

Why it applies: the release compares against a previous estimate

PEA-Supportingneutral

Resource estimate prepared to support a Preliminary Economic Assessment — early-stage study.

Why it applies: the release names the study this estimate supports

indicatedCauchari-Olaroz · lithiumTonnes: 11299172Grade: 571Grade Unit: mg/LContained Metal: 11299172Contained Unit: tView all details
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Identity

Project
Cauchari-Olaroz
Commodity
lithium
Region
argentina
Reported Region
Jujuy Province, Argentina
Ticker
LAR

Resource scope

Estimate type
resource
Effective date
2025-12-31T00:00:00.000Z
Reporting standards
ni_43_101
QP Signed
Yes
Qualified person names
Mark King
Resource group id
resource:42a7e9d5b8f8d3951d04
Ownership percent
44.8 %

Resource Data

Category
indicated
Tonnes
11299172
Grade
571
Grade Unit
mg/L
Contained Metal
11299172
Contained Unit
t
Cutoff Grade
300
Cutoff Unit
mg/L

Prior Estimate

Resource Date
2025-12-31

Review

Needs Review
No
Historical
No

Dates

Event date
2026-03-11T00:00:00.000Z

Reasoning: Standard indicated resource component of the update.

Evidence · table

“11,299,172”

Context: 3.87E+ 10

Tags used in scoring

Indicated Resourcepositive

Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves.

Why it applies: category is "indicated"

Cut-off Disclosedpositive

Cut-off grade used for resource reporting is clearly stated, enabling like-for-like comparison.

Why it applies: cutoff_grade is stated

QP/CP Signedpositive

Qualified Person (QP) or Competent Person (CP) named and signed off — a member of a recognized professional association (e.g., AusIMM, SME, AIG, P.Geo) with relevant experience.

Why it applies: qp_signed is true

NI 43-101 Compliantpositive

Resource estimate prepared in compliance with NI 43-101 (Canada) — high reporting standard.

Why it applies: reporting_standards includes ni_43_101

Resource Updateneutral

Revised estimate for an existing resource — compare to prior to assess progress.

Why it applies: the release compares against a previous estimate

PEA-Supportingneutral

Resource estimate prepared to support a Preliminary Economic Assessment — early-stage study.

Why it applies: the release names the study this estimate supports

inferredCauchari-Olaroz · lithiumTonnes: 9614004Grade: 567Grade Unit: mg/LContained Metal: 9614004Contained Unit: tView all details
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Identity

Project
Cauchari-Olaroz
Commodity
lithium
Region
argentina
Reported Region
Jujuy Province, Argentina
Ticker
LAR

Resource scope

Estimate type
resource
Effective date
2025-12-31T00:00:00.000Z
Reporting standards
ni_43_101
QP Signed
Yes
Qualified person names
Mark King
Resource group id
resource:fe92588ee082f8bfc630
Ownership percent
44.8 %

Resource Data

Category
inferred
Tonnes
9614004
Grade
567
Grade Unit
mg/L
Contained Metal
9614004
Contained Unit
t
Cutoff Grade
300
Cutoff Unit
mg/L

Prior Estimate

Resource Date
2025-12-31

Review

Needs Review
No
Historical
No

Dates

Event date
2026-03-11T00:00:00.000Z

Reasoning: Strong growth in the inferred category adds to the project's long-term potential.

Positive factors

  • Significant expansion of inferred resource

Evidence · table

“9,614,004”

Context: 2.77E+ 10

Tags used in scoring

Inferred Resourcenegative

Speculative category — limited drilling, geological continuity assumed but not confirmed. Cannot support economic studies alone.

Why it applies: category is "inferred"

Cut-off Disclosedpositive

Cut-off grade used for resource reporting is clearly stated, enabling like-for-like comparison.

Why it applies: cutoff_grade is stated

QP/CP Signedpositive

Qualified Person (QP) or Competent Person (CP) named and signed off — a member of a recognized professional association (e.g., AusIMM, SME, AIG, P.Geo) with relevant experience.

Why it applies: qp_signed is true

NI 43-101 Compliantpositive

Resource estimate prepared in compliance with NI 43-101 (Canada) — high reporting standard.

Why it applies: reporting_standards includes ni_43_101

Resource Updateneutral

Revised estimate for an existing resource — compare to prior to assess progress.

Why it applies: the release compares against a previous estimate

PEA-Supportingneutral

Resource estimate prepared to support a Preliminary Economic Assessment — early-stage study.

Why it applies: the release names the study this estimate supports

provenCauchari-Olaroz · lithiumTonnes: 0.4Grade: 588Grade Unit: mg/LContained Metal: 0.4Contained Unit: mtView all details
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Identity

Project
Cauchari-Olaroz
Commodity
lithium
Region
argentina
Reported Region
Jujuy Province, Argentina
Ticker
LAR

Resource scope

Estimate type
reserve
Effective date
2026-01-01T00:00:00.000Z
Reporting standards
ni_43_101
QP Signed
Yes
Qualified person names
Mark King
Resource group id
resource:b8bf0726fb95c43e8a38
Ownership percent
44.8 %

Resource Data

Category
proven
Tonnes
0.4
Grade
588
Grade Unit
mg/L
Contained Metal
0.4
Contained Unit
mt
Cutoff Grade
300
Cutoff Unit
mg/L

Prior Estimate

Resource Date
2026-01-01

Review

Needs Review
No
Historical
No

Dates

Event date
2026-03-11T00:00:00.000Z

Reasoning: Proven reserves show growth due to improved hydrogeological understanding.

Positive factors

  • Proven reserves increased by 45% vs 2019

Evidence · table

“0.4”

Context: 227,782,565

Tags used in scoring

Proven Reservepositive

Measured Resource with demonstrated economic viability after applying modifying factors.

Why it applies: category is "proven"

Cut-off Disclosedpositive

Cut-off grade used for resource reporting is clearly stated, enabling like-for-like comparison.

Why it applies: cutoff_grade is stated

QP/CP Signedpositive

Qualified Person (QP) or Competent Person (CP) named and signed off — a member of a recognized professional association (e.g., AusIMM, SME, AIG, P.Geo) with relevant experience.

Why it applies: qp_signed is true

NI 43-101 Compliantpositive

Resource estimate prepared in compliance with NI 43-101 (Canada) — high reporting standard.

Why it applies: reporting_standards includes ni_43_101

Resource Updateneutral

Revised estimate for an existing resource — compare to prior to assess progress.

Why it applies: the release compares against a previous estimate

PEA-Supportingneutral

Resource estimate prepared to support a Preliminary Economic Assessment — early-stage study.

Why it applies: the release names the study this estimate supports

probableCauchari-Olaroz · lithiumTonnes: 1Grade: 572Grade Unit: mg/LContained Metal: 1Contained Unit: mtView all details
Link to this fact

Identity

Project
Cauchari-Olaroz
Commodity
lithium
Region
argentina
Reported Region
Jujuy Province, Argentina
Ticker
LAR

Resource scope

Estimate type
reserve
Effective date
2026-01-01T00:00:00.000Z
Reporting standards
ni_43_101
QP Signed
Yes
Qualified person names
Mark King
Resource group id
resource:dcf3cf296b401b1b754d
Ownership percent
44.8 %

Resource Data

Category
probable
Tonnes
1
Grade
572
Grade Unit
mg/L
Contained Metal
1
Contained Unit
mt
Cutoff Grade
300
Cutoff Unit
mg/L

Prior Estimate

Resource Date
2026-01-01

Review

Needs Review
No
Historical
No

Dates

Event date
2026-03-11T00:00:00.000Z

Reasoning: Probable reserves form the bulk of the current reserve base.

Evidence · table

“1.0”

Context: 526,320,091

Tags used in scoring

Probable Reservepositive

Indicated Resource with demonstrated economic viability after applying modifying factors.

Why it applies: category is "probable"

Cut-off Disclosedpositive

Cut-off grade used for resource reporting is clearly stated, enabling like-for-like comparison.

Why it applies: cutoff_grade is stated

QP/CP Signedpositive

Qualified Person (QP) or Competent Person (CP) named and signed off — a member of a recognized professional association (e.g., AusIMM, SME, AIG, P.Geo) with relevant experience.

Why it applies: qp_signed is true

NI 43-101 Compliantpositive

Resource estimate prepared in compliance with NI 43-101 (Canada) — high reporting standard.

Why it applies: reporting_standards includes ni_43_101

Resource Updateneutral

Revised estimate for an existing resource — compare to prior to assess progress.

Why it applies: the release compares against a previous estimate

PEA-Supportingneutral

Resource estimate prepared to support a Preliminary Economic Assessment — early-stage study.

Why it applies: the release names the study this estimate supports

How Atlas produces this analysis

Minestarters Atlas uses automated extraction to summarize mining announcements, identify reported measurements, and classify supporting evidence. Sentiment reflects the extracted narrative and classification rules; it is an interpretation, not a reported measurement. Evidence quotes and context are provided where available. Missing data, low-confidence results, and review flags indicate limitations. Check the original publisher announcement before relying on an interpretation.