Full-scale installations of the InLine Pressure Jig (IPJ) continuous gravity recovery (CGR) circuits at Pirquitas (Silver Standard Resources) and Kloof (Gold Fields) have provided further evidence of the strong correlation of Gekko's CGR laboratory test work protocol and plant results.
In both instances, the preliminary test work was undertaken in Gekko's metallurgical laboratory, utilising Viking Cone and tabling test work where appropriate.
Both circuits have substantially different flow sheets with IPJs operating in different particle size ranges. In the case of Pirquitas the IPJs treat particle sizes in the 2-12mm size range and perform a critical gangue rejection function.
Testwork
Extensive gravity characterization testwork was conducted at Gekko's laboratory in Ballarat, the University of Technology at Oruro, Bolivia and Gekko's Peruvian agent, Futuratech. The results indicated that the ore contained at the Mina Pirquitas mine site could be separated at a crush size of 12mm into 50% of the mass with less than 5% silver loss.
Key tests conducted during the program include size distribution analyses, single pass tabling tests and dense media 'Gekko Viking Cone' testing.
The Viking test is particularly suited to determining the recovery and mass yield that can be obtained using the IPJ at coarse sizes
Plant Design
Based on the testwork, Gekko Systems designed a plant to treat the ore at an efficient operating cost and optimum recovery. The plant design included the following features:
- 214tph throughput
- six IPJ2400s in two stages of three parallel trains
- Rougher-scavenger jig circuit design to allow for high mass pull to concentrate
- The IPJ2400 was de-rated from a nominal 100tph to 75tph each due to the high mass pull to concentrate required
- A water recovery and recycle system recovers water from the IPJ heavies and lights and the water is re-injected to feed the jig circuit
The water recovery system enhances the low environmental footprint of the plant.
Plant Performance
There is a strong correlation between test and actual plant results. The plant data follows the main trend and stays within the variances seen in the Gekko testwork results.
Trevor Yeomans, Director of Metallurgy at Silver Standard, commented: "The commissioning process has gone exceptionally well and the performance of the plant has exceeded the initial lab testwork recoveries."
The higher grade produced by the IPJ circuit resulted in increased silver flotation recovery at a higher concentrate grade in the downstream milling and flotation circuit.
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