Atomic Eagle Hits 86% Uranium Recovery at Muntanga East With Low Acid Use
Key Takeaways
- Mintek's testwork on Muntanga East diamond core delivered uranium recoveries of 81% to 86%, matching earlier programs despite a lower ~167 ppm U3O8 head grade.
- Acid consumption was ~3 kg/t at the extraction stage, with extraction substantially complete after ~20 days of leaching.
- Column leach tests recovered 80.8% to 81.0% over 62 days but used 7.0 to 7.6 kg/t of acid in total, so the headline acid figure covers only the early extraction period.
- Hydraulic conductivity of about 4,537 to 4,396 L/m2/h is more than four times the typical heap leach design threshold, supporting physical suitability for a 6-metre heap.
- The results feed into ongoing technical studies for the 58.8Mlb Muntanga Project, but no timelines, costings or production targets were disclosed.
Muntanga East heap leach tests deliver ~81% to ~86% uranium recoveries
Atomic Eagle (ASX: AEU) has announced results from Mintek metallurgical test work on diamond core from the recently discovered Muntanga East deposit, part of its 100%-owned Muntanga Uranium Project in Zambia. Leach tests achieved uranium recoveries of between ~81% and ~86%.
Acid consumption was low at ~3 kg/t during the uranium extraction period, and extraction was substantially complete after ~20 days of leaching. The Company says the diamond core samples are representative of the Muntanga East resource.
For investors, the message is that the favourable heap leach metallurgy at Muntanga extends beyond the historical deposits. That adds confidence in how uranium deposits in this region perform.
Phil Hoskins, Chief Executive Officer, Atomic Eagle
“One of the defining strengths of the Muntanga Project is its ability to achieve high uranium recoveries through simple heap leach processing with low reagent consumption…”
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Bottle roll and column leach results
Test program and results
Mintek, working in South Africa, tested two composite samples (ME1 and ME2) prepared from diamond drill core. The material was crushed to a nominal top size of 25 mm, with an average uranium head grade of approximately 167 ppm U3O8.
Head grade is the average uranium content of the material fed into the test. This was lower-grade mineralisation than has historically been tested from several of the Project’s other deposits, yet recoveries were in line with previous programs.
| Test type | Composite | Uranium recovery | Acid consumption | Duration |
|---|---|---|---|---|
| Bottle roll | ME1 | 85.9% | ~3 kg/t | 25 days |
| Bottle roll | ME2 | 81.9% | ~3 kg/t | 25 days |
| Column leach | ME1 | 81.0% | 7.0 kg/t | 62 days |
| Column leach | ME2 | 80.8% | 7.6 kg/t | 62 days |
Column tests used 1-metre-high columns operating under conditions representative of heap leach processing. Note the acid figures measure different things: ~3 kg/t applied at the extraction stage (around 15 to 20 days), while 7.0 to 7.6 kg/t is the total across the full 62-day column test.
Rapid leaching kinetics
Kinetics describe how quickly uranium dissolves. The announcement highlights:
- Bottle roll dissolution was effectively complete after approximately seven days.
- Approximately 80% of the uranium in the ore occurs in minerals that dissolve readily under conventional acid heap leach conditions.
- Column dissolution curves flattened after approximately 15 to 20 days, with only modest additional recovery over the remainder of the 62-day test.
Faster extraction at lower acid use points towards lower reagent needs. The Company says this shows the majority of uranium can be recovered with very low acid consumption.
Heap leach basics and why low acid matters
Heap leaching is a low-tech way to extract metal. Crushed ore is stacked in a heap, acid solution percolates through it, and the uranium dissolves and is then recovered from the solution.
Acid is a running input, so how much the process consumes matters to operating costs. Recovery on lower-grade ore matters too, because it influences whether that material can be mined economically.
Mr Hoskins said the Project’s ability to achieve high recoveries with low reagent consumption “allows lower grade uranium mineralisation to be mined and recovered economically.” The announcement describes the acid use as significantly below the average achieved across the broader Muntanga Project, but gives no comparative figure.
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Physical characteristics and next steps for Muntanga
Physical suitability
A heap only works if solution can flow through it. Testing found:
- Low fines content and minimal fines generation during leaching, reducing the risk of permeability loss.
- Favourable bulk density and porosity in stacking assessments simulating a heap height of 6 metres.
- Hydraulic conductivity of approximately 4,537 L/m2/h to 4,396 L/m2/h, more than four times the design threshold typically required for heap leaching operations.
Hydraulic conductivity measures how readily solution moves through the material.
What comes next
The results will be incorporated into ongoing technical studies supporting the continued advancement of the Project. The Company says they provide additional confidence in the potential integration of Muntanga East into future mine development planning.
Mr Hoskins pointed to Muntanga East’s shallow mineralisation and close proximity to the central resource area. The announcement gives no timelines, costings or production targets.
Atomic Eagle describes Muntanga as containing a JORC Mineral Resource of 58.8Mlbs at 309ppm U₃O₈. The metallurgical test work is based on information reviewed by Dr Stefan Robertson of Mintek, who carried out the test work and is a Competent Person under the JORC Code.
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