# AHK: ANSTO TEST RESULTS - 98-99% LREO EXTRACTION FROM SANDY M

Canonical Atlas analysis: https://atlas-staging.minestarters.com/news/ahk-ansto-test-results-98-99-lreo-extraction-from-sandy-m--6610ccaa-15fa-4b87-a942-0586719ee4e9

Original source: https://www.asx.com.au/asx/v2/statistics/displayAnnouncement.do?display=pdf&idsId=03150074

Publisher: asx

Original announcement: 2026-10-08T00:24:00.000Z

Analysis by Minestarters Atlas

Atlas analysis published: 2026-10-08T01:32:02.593Z

Atlas analysis updated: 2026-10-08T01:32:02.593Z

- Company: Ark Mines Ltd

- Ticker: AHK

- Exchange: ASX

- Region: North Queensland

- Primary commodity: Rare earths

- Secondary commodities: Dysprosium, Yttrium

- Document categories: Metallurgy

- Extracted: 2026-10-08 01:32:03 UTC

Narrative sentiment: 0.80 · Bullish

## Minestarters Atlas summary

Ark Mines reports successful scoping metallurgical testwork by ANSTO on monazite concentrate from the Sandy Mitchell project. The tests achieved 98-99% light rare earth extraction via acid bake and ~98% via caustic conversion, demonstrating processing flexibility.

Reasoning: The scoping metallurgical testwork demonstrates high recovery rates for light rare earths using conventional processing routes, providing significant de-risking for the project's flowsheet development.

- Positive factor: High light rare earth extraction \(98-99%\)

- Positive factor: Amenable to both acid bake and caustic conversion routes

- Positive factor: High phosphate removal \(97%\)

- Positive factor: Excellent monazite liberation \(93%\)

- Negative factor: Scoping-level results only

- Negative factor: Does not include monazite recovery from ore to concentrate

Facts used in scoring: 4

## Classification and evidence

**High Recovery**

Polarity: positive

Definition: Recovery at or above the exceptional band for the commodity and processing route.

Why it applies: LRE extraction achieved up to 99.6% via acid bake and 98% via caustic leach.

Evidence · text

> achieving high light rare earth extractions of 98% to 99%

**Mill Route**

Polarity: neutral

Definition: Processing via mill or concentrator \(CIL, CIP, tank leach, flotation\).

Why it applies: The primary testwork involved milled concentrate \(P80 43um\).

Evidence · text

> two on milled concentrate \(P80 of 43μm\)

**Gravity Route**

Polarity: neutral

Definition: Gravity separation forms a material part of the flowsheet.

Why it applies: the document describes a gravity route \("gravity"\)

**Multi-Domain Tested**

Polarity: positive

Definition: Variability across ore domains \(oxide, transition, fresh\) has been addressed.

Why it applies: 3 distinct composites were tested

## Extracted facts

Stored fact records: 4. Some facts used in scoring do not have a stored record.

## Metallurgical Results (4)

### acid bake and water leach

[Link to this fact](https://atlas-staging.minestarters.com/news/ahk-ansto-test-results-98-99-lreo-extraction-from-sandy-m--6610ccaa-15fa-4b87-a942-0586719ee4e9#fact-metallurgical-facts-0)

Sandy Mitchell · rare\_earths

#### Identity

- Project: Sandy Mitchell
- Commodity: rare\_earths
- Region: australia\_qld
- Reported Region: North Queensland
- Ticker: AHK

#### Test Work

- Program Status: scoping
- Test Type: acid bake and water leach
- Processing Route: acid bake and water leach
- Sample: milled monazite concentrate \(P80 43um\), 1,100kg/t acid addition
- Grind P80: 43 µm

#### Recovery

- Recovery: 98 %
- Recovery Basis: actual\_test
- Head Grade: 48.7
- Head Grade Unit: % TREO

#### Lab

- Laboratory: ANSTO

#### Review

- Needs Review: No
- Historical: No

#### Dates

- Event date: 2026-10-08T00:00:00.000Z

Reasoning: 98% recovery is strong for a scoping-level acid bake test.

- Positive factor: High recovery at standard acid addition

Evidence · text

> light rare earth \(LRE\) extraction from the milled concentrate increased from 98% at 1,100kg/t acid addition

### acid bake and water leach

[Link to this fact](https://atlas-staging.minestarters.com/news/ahk-ansto-test-results-98-99-lreo-extraction-from-sandy-m--6610ccaa-15fa-4b87-a942-0586719ee4e9#fact-metallurgical-facts-1)

Sandy Mitchell · rare\_earths

#### Identity

- Project: Sandy Mitchell
- Commodity: rare\_earths
- Region: australia\_qld
- Reported Region: North Queensland
- Ticker: AHK

#### Test Work

- Program Status: scoping
- Test Type: acid bake and water leach
- Processing Route: acid bake and water leach
- Sample: milled monazite concentrate \(P80 43um\), 1,500kg/t acid addition
- Grind P80: 43 µm

#### Recovery

- Recovery: 99.6 %
- Recovery Basis: actual\_test
- Head Grade: 48.7
- Head Grade Unit: % TREO

#### Lab

- Laboratory: ANSTO

#### Review

- Needs Review: No
- Historical: No

#### Dates

- Event date: 2026-10-08T00:00:00.000Z

Reasoning: 99.6% extraction is exceptional for this processing route.

- Positive factor: Near-total extraction of light rare earths

Evidence · text

> ~99.6% at 1,500kg/t

### acid bake and water leach

[Link to this fact](https://atlas-staging.minestarters.com/news/ahk-ansto-test-results-98-99-lreo-extraction-from-sandy-m--6610ccaa-15fa-4b87-a942-0586719ee4e9#fact-metallurgical-facts-2)

Sandy Mitchell · rare\_earths

#### Identity

- Project: Sandy Mitchell
- Commodity: rare\_earths
- Region: australia\_qld
- Reported Region: North Queensland
- Ticker: AHK

#### Test Work

- Program Status: scoping
- Test Type: acid bake and water leach
- Processing Route: acid bake and water leach
- Sample: unmilled monazite concentrate \(P80 170um\), 1,500kg/t acid addition
- Grind P80: 170 µm

#### Recovery

- Recovery: 95 %
- Recovery Basis: actual\_test
- Head Grade: 48.7
- Head Grade Unit: % TREO

#### Lab

- Laboratory: ANSTO

#### Review

- Needs Review: No
- Historical: No

#### Dates

- Event date: 2026-10-08T00:00:00.000Z

Reasoning: 95% recovery is good, but confirms kinetic limitations at coarser sizes.

- Positive factor: Still achieves high recovery despite coarser grind

- Negative factor: Lower recovery than milled concentrate

Evidence · text

> unmilled concentrate returned a lower LRE extraction of 95%

### caustic conversion and hydrochloric acid leach

[Link to this fact](https://atlas-staging.minestarters.com/news/ahk-ansto-test-results-98-99-lreo-extraction-from-sandy-m--6610ccaa-15fa-4b87-a942-0586719ee4e9#fact-metallurgical-facts-3)

Sandy Mitchell · rare\_earths

#### Identity

- Project: Sandy Mitchell
- Commodity: rare\_earths
- Region: australia\_qld
- Reported Region: North Queensland
- Ticker: AHK

#### Test Work

- Program Status: scoping
- Test Type: caustic conversion and hydrochloric acid leach
- Processing Route: caustic conversion and hydrochloric acid leach
- Sample: ground monazite concentrate, caustic conversion + HCl leach

#### Recovery

- Recovery: 98 %
- Recovery Basis: actual\_test
- Head Grade: 48.7
- Head Grade Unit: % TREO

#### Lab

- Laboratory: ANSTO

#### Review

- Needs Review: No
- Historical: No

#### Dates

- Event date: 2026-10-08T00:00:00.000Z

Reasoning: Demonstrates high recovery and effective impurity removal via caustic route.

- Positive factor: High recovery via caustic route

- Positive factor: High phosphate removal \(97%\)

Evidence · text

> delivering approximately 98% light rare earth extraction

## 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.