Gravity/Flotation test protocols

Gekko’s IPJ and flash flotation are processing methods which remove gold or other minerals from a comminution circuit. They are complementary technologies and in many cases have been used together to maximise gold recovery in size ranges at which they operate. The combination of flash flotation and continuous gravity recovery covers the full size range from 10μm up to millimetres sizes. (Dominy, Murphy, Gray, 2011).

Utilising both the IPJ and flotation cells, Gekko has developed a test protocol utilising a Vertical Shaft Impactor (VSI) crushing stage, followed by coarse gravity
recovery, then finally the use of flotation to recover fine particles unrecovered by gravity. This technique is expected to recover the minerals between the 100μm and 250μm size range where there is a cross over between the recovery capabilities of both gravity recovery and flotation. Gravity separation can be used to recover the mineral down to the 100μm size range. Flash flotation can then recover the particles from the 150μm down to 10μm. This is clearly demonstrated in the chart below, adapted from the original version developed by Napier-Munn and Wills 2006.

This style of flow sheet has been utilised in Gekko’s award-winning Python plant and varies from conventional test protocols which recirculate the tails back through the crushing/grinding stages before it reports to the flotation cells. The Python was designed to treat ores that have high amenability to a combination of gravity and flotation. The Python capability was based around coarse separations but is now being broadened to accept finer feeds and a wider range of mineral types.