The Gekko Python 500 modular processing plant was originally developed to process ore in an underground environment. However, recent customer demand and subsequent reconfiguration changes have enabled the new Python 2500 to be applied to low-grade surface applications. “This new Python model has low capital and operating costs, fast delivery and installation, as well as low energy consumption and infrastructure requirements. The modularity of the Python system allowed for the simple circuit changes/reconfiguration and enabled this alternative flowsheet.” Tim Hughes, Gekko’s Process Engineering Manager, said.
This has been achieved by reviewing the natural gold size distribution in waste dumps and taking advantage of the difference in crushability of the gold-bearing mineral versus the waste. The throughput rate of the Python has been increased to a nominal 250 t/h with minimal reduction in recovery from the application of gangue rejection concepts. Gekko has labelled this innovative, high volume model, the Python 2500 (P2500). The development is aimed at producing a gravity and flotation concentrate from the waste rock dumps, incorporating:
- Single pass Vertical Shaft Impactor (VSI) crushing of the minus 32 mm feed from the waste rock dumps
- Wet screening at 3 mm with rejection of the plus 3 mm fraction to tailings
- InLine Pressure Jig (IPJ) rougher pre-concentration of the minus 3 mm fraction
- Wet screening of the rougher IPJ tails at nominally 1.4 mm with rejection of the +1.4 mm to tailings and the minus 1.4 mm sent to flotation
- IPJ cleaner concentration of the rougher IPJ concentrate with IPJ cleaner concentrate sent to concentrate treatment
- Wet screening of the IPJ cleaner tail at nominally 1.4 mm with closed circuit VSI crushing of the plus 1.4 mm fraction
- Water recovery using hydro-cyclones and recycle water tank from the minus 1.4 mm fractions
- Flotation of gold and sulphides from the minus 1.4 mm (nominal) stream using purpose built flash flotation or similar cells.
Gold Fields South Africa has been a long-term supporter of Gekko equipment and over the last 12 months the company has been working very closely with Gekko’s Technical Team on several current and future projects. The reviews on these projects are providing the basis for the Gold Fields KDC East project. This project will use Gekko’s Python technology to provide a cost effective and energy efficient method for processing waste rock dumps. Since the installation of the Python 500 at Gold Fields’ Kloof project, Gold Fields has provided samples to Gekko’s metallurgical laboratory from their projects around the world. The test work protocols are based on further investigation of the ore suitability for the Python 2500 concept.
The Python technology appealed to Gold Fields as a practical rock treatment metallurgical solution together with its benefits around modularity and energy efficiency. It was from this base that the initial project gathered momentum, culminating in the installation of the initial Python at KDC Operations in South Africa in 2011. The current Python 500 at KDC will soon be upgraded to treat 250 t/h. The increased throughput will allow Gold Fields to process the waste material at a significantly accelerated rate. It will also take advantage of learnings that have been gained from operations to date which highlight that up to 80% of the gold is contained in a relatively fine component of the waste material. The upgraded flow sheet utilises this to full advantage, whilst still maintaining the energy efficiency inherent in the fine crush and pre-concentration approach utilising the IPJ in combination with flotation.