The technical and metallurgical laboratory team at Gekko Systems specialises in the design of gravity and intensive leach test research programs.
Key areas of expertise include determining the recovery of minerals at their liberation size, grade recovery relationships, size recovery relationships, as well as recovery of auriferous minerals through intensive leach work.
Continuous gravity recovery or CGR test work protocols are an alternative to the standard batch gravity recovery (GRG) test work program offered in many independent laboratories.
CGR testwork provides a significantly better understanding of an ore’s response to gravity separation systems by plotting the recovery against a mass yield. As a result, Gekko’s technical staff would generally recommend a CGR test to be undertaken on ores over the standard GRG test.
Gekko’s technical group led by Technical Director, Sandy Gray and R&D Manager, Tim Hughes has developed and synced protocols to replicate the continuous gravity recovery of heavies and lights in mineral processing circuits.
This has been an important development in assessing the performance opportunity of the inline pressure jigs in processing plants.
Gekko’s team has developed two CGR test work programs that replicate IPJ performance and are designed to simulate single pass or re-circulating load circuit designs.
CGR single pass test work
The CGR test simulates the performance of the IPJ in a single pass set up in crushing and grinding circuits.
The CGR test uses dense media separation at coarse sizes for size fractions above 1.2mm and tabling for size fractions at less than 1.2mm. The top crush size for the CGR test is 12mm.
The purpose of the test is to determine the SG differential of the sample and the results are then plotted on a yield recovery curve.
The heavies are collected at different mass yields and recovery of valuable minerals is determined. It is possible to determine the optimum mass yield from the curve, to recover or reject the heavies or lights.
CGR progressive grind for circulating loads
Where the IPJ is to be installed in a circular load, the CGR test is modified such that heavies are removed at the coarse size as they liberate and the lights from the test are then represented at finer crush or grind sizes to replicate the environment experienced in re-circulating loads.
The two test work programs discussed here are becoming increasingly popular in the Gekko metallurgical lab as customers focus on strategies to reject gangue or pre-concentrate their target mineral in order to reduce capital, energy consumption and operating costs.
Comminution strategy critical to optimising gravity concentration
Gekko has invested in securing a range of comminution devices to optimise the CGR test work program.
According to R&D manager, Tim Hughes, the comminution method is the single most important factor in maximising gravity separation resulting in the lab being equipped with various test crushing and grinding devices such as VSI, HPGR, conventional crushing and conventional milling.
He adds that Gekko has recently developed their own lab unit to replicate the VSI unit performance in fine crushing and circulating loads.