Compiled and Edited by: Dr. Nader Salek
August 2026
Introduction
In many gold mines, the main issue is not just extracting the ore; a significant part of the mine’s economic value can be lost in the tailings, low-grade concentrates, and intermediate streams of the processing plant.
Therefore, the goal of a modern plant should not merely be to increase capacity; it must also seek to maximize gold recovery from each ton of ore and minimize the gold remaining in the final tailings.
1. The Starting Point: Precise Knowledge of Gold
Before selecting any technology, it must be determined whether the gold is:
- Free or locked within other minerals;
- What its particle size is;
- What minerals it is associated with;
- In which part of the circuit the greatest losses occur.
Gold grade analysis in the feed, concentrate, and especially the final tailings must be accompanied by mineralogical studies and liberation size determination.
Without this step, increasing capacity or purchasing new technology may only increase capital expenditure.
2. Recovering Free Gold; Gravity Processing
If a significant portion of the gold is free, advanced gravity methods can be the first option for recovery.
Specialized gold centrifuges, including equipment used in industrial circuits, are applicable for recovering free and fine gold particles.
In tailings reprocessing projects, a dedicated gravity circuit can be designed for the tailings stream to investigate the recoverable gold.
3. Fine and Ultrafine Gold; The Advent of Nanobubble Technology
If a significant portion of the gold is very fine, conventional flotation may not achieve full recovery potential.
At this point, nanobubble technology becomes important.
Nanobubbles can improve the contact conditions between bubbles and fine particles and can be used in the flotation of gold-bearing minerals, especially sulfide minerals.
Recent studies on specific ores have shown that using nanobubbles can increase recovery and concentrate grade compared to conventional flotation; however, these results must be tested and confirmed independently for each ore type.
4. When Gold is Locked; Targeted Liberation
If mineralogical studies show that gold is locked within pyrite, arsenopyrite, or other sulfide minerals, the solution is not necessarily nanobubbles.
In these conditions, the liberation level must first be increased.
Regrinding and controlled milling can be effective in liberating gold; however, excessive grinding can consume a lot of energy and make processing ultrafine particles more difficult.
Therefore, the goal is not more grinding; it is optimal grinding for economic gold liberation.
5. Refractory Ore; BIOX and POX
In refractory ores, even after suitable grinding, gold may remain locked within the sulfide mineral structure.
In such conditions, technologies such as:
- BIOX or bio-oxidation
- POX or pressure oxidation
can be used to destroy the host mineral structure and prepare the gold for the subsequent processing stage.
These two technologies differ from many nanotechnologies in terms of industrial maturity and have operational track records in commercial projects processing refractory ores.
6. Tailings Reprocessing; A Second Mine Inside the Plant
One of the most attractive projects for increasing gold production is examining existing tailings.
If the tailings contain an economic amount of gold, a significant portion of the remaining gold can be recovered using an independent circuit comprising:
Classification, Gravity Separation, Flotation, Nanobubbles, and Leaching if necessary.
The advantage of this approach is that it creates economic value from material previously discarded as waste, without the need to extract new volumes of rock.
7. Increasing Capacity; After Proving Recovery
Increasing plant capacity is valuable only after the existing process has been optimized for recovery.
If a plant with low recovery increases its capacity, it may simply transfer more gold to the tailings.
Therefore, the logical sequence is:
Identifying Gold Loss
Metallurgical Testing
Circuit Optimization
Piloting New Technology
Economic Calculation
Then Capacity Increase
8. Proposed Maximum Recovery Circuit
For a real project, the following circuit could be studied:
- Ore
- Controlled Crushing and Grinding
- Gravity Concentration
- Flotation
- Nanobubble Flotation for the fines fraction
- BIOX or POX Pretreatment if the ore is refractory
- Leaching
- Gold Recovery from Solution
- Smelting and Doré Production
And in parallel:
- Final Tailings
- Classification
- Gravity Recovery
- Nanobubble Flotation
- Leaching of Residue if Economically Justified
Conclusion
To achieve maximum gold recovery, a single technology cannot be a universal solution for all mines.
The professional approach is to design a dedicated processing circuit based on the specific mineralogy of that mine.
In ores with free gold, gravity methods can play a significant role. For fine and ultrafine particles, nanobubbles are a viable option for investigation and piloting. In refractory ores, BIOX and POX can play a key role, and finally, tailings reprocessing can be an independent source for increasing gold production.
Therefore, the project’s success indicator is not just “plant capacity”; rather, the actual recovery percentage, the amount of gold remaining in the tailings, and the total cost per ounce of recovered gold must be evaluated simultaneously.
Dr. Nader Salek
Consultant & Trade Facilitator
GHAVFEL AL-LOLO Company (GHLOLO)
A Subsidiary of Salek Trading Group
Website: www.Ghloloco.com
Email: info@Ghloloco.com
CC: Ghlolo@gmail.com
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