Knelson Concentrator Performance and Cleangold Loss Reduction Strategy
Based on the Cleangold Report on Artminer’s Project in Xinjiang, China (October 2013), the following details outline the operational role of the Knelson concentrators, their identified performance limitations, and how Cleangold technology is positioned to address the resulting gold losses.
Knelson Concentrator Operational Context
The Knelson concentrators serve as the primary gravity recovery unit in the mine’s processing circuit. The specific operational parameters and flow are as follows:
- Feed Material: The entire crushed ore stream is processed.
- Particle Size: Ore is crushed to minus 200 mesh.
- Gold Characteristics: The gold is predominantly less than 200 mesh in size and frequently coated with pyrite.
- Process Flow:
- Concentrates: Sent directly to closed-circuit cyanide extraction.
- Tailings: Forwarded to the flotation circuit for further concentration before cyanide leaching.
Identified Performance Limitations
The report highlights specific inefficiencies in the Knelson concentrator stage, which contribute to downstream losses:
- Poor Recovery of Fine Particles: Laboratory testing at the mine indicated that Knelson concentrators performed poorly on the fraction of gold smaller than 200 mesh.
- Pyrite Coating Interference: The common presence of pyrite coatings on gold particles likely hinders effective gravity separation in the Knelson units.
- Downstream Impact: Because the Knelson tailings are sent to flotation, any gold not recovered by the Knelson concentrators must be captured by flotation. However, the flotation process itself is not 100% efficient, leading to residual losses in the final tailings.
Cleangold Technology as a Loss Reduction Solution
The report positions Cleangold technology as a supplementary method to recover gold lost in flotation tailings, which include the Knelson tailings stream.
Targeted Losses
- Flotation Tailings Concentration: The tailings from the flotation process (which processes the Knelson tailings) run at approximately 0.5 grams per ton.
- Economic Impact: At a processing rate of 1,000 tons per day, this loss represents an estimated $20,000 per day in unrecovered gold.
Cleangold Demonstration Results
- Method: Cleangold engineers processed a sample of the flotation tailings using a Prospector’s Sluice precharged with an engineered magnetite matrix.
- Outcome: The team successfully collected high-density samples for microscopic examination, confirming the presence of recoverable gold in the tailings.
- Implication: This demonstrates that Cleangold technology can effectively scavenge fine, pyrite-coated gold particles that were missed by both the Knelson concentrators and the flotation circuit.
Summary of Process Losses and Cleangold Intervention
| Process Stage | Material Stream | Gold Concentration (g/t) | Issue Identified | Cleangold Role |
|---|---|---|---|---|
| Gravity (Knelson) | Knelson Tailings | N/A (Sent to Flotation) | Poor recovery of <200 mesh, pyrite-coated gold | Upstream cause of downstream losses |
| Flotation | Flotation Tailings | ~0.5 | Residual gold loss after flotation | Direct Target: Cleangold recovers gold from this stream |
| Cyanide Leaching | Leach Tailings | ~5.0 | Losses from concentrates (less significant due to low tonnage) | Not the primary focus of this report |
Conclusion
The report identifies that the Knelson concentrators have limited efficiency on fine, coated gold, leading to losses that persist through the flotation stage. Cleangold technology is presented as a viable solution to reduce these specific tailings losses by recovering the remaining fine gold particles that the existing gravity and flotation circuits failed to capture.
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