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Gangue rejection circuit increases Python throughput by five times

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Gekko Systems  has introduced a new Python model that delivers increased throughput and energy efficiency at low capital and operating costs.

Python 500 modular processing plants were originally developed for ore processing in an underground environment. However, recent customer demand and subsequent reconfiguration changes have enabled the Python to be applied to low-grade surface applications.

Tim Hughes, Gekko’s Process Engineering Manager explains that the new Python 2500 also enables fast delivery and installation with low energy consumption and infrastructure requirements. The modularity of the Python system allowed for the simple circuit changes/ reconfiguration to enable this alternative flowsheet.

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 tph with minimal reduction in recovery from the application of gangue rejection concepts.

The Python 2500 aims to produce a gravity and flotation concentrate from the waste rock dumps incorporating:

  • Single pass Vertical Shaft Impactor (VSI) crushing of the minus 32mm feed from the waste rock dumps
  • Wet screening at 3mm with rejection of the plus 3mm fraction to tailings
  • InLine Pressure Jig (IPJ) rougher pre-concentration of the minus 3mm fraction
  • Wet screening of the rougher IPJ tails at nominally 1.4mm with rejection of the +1.4mm to tailings and the minus 1.4mm 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 1.4mm with closed circuit VSI crushing of the plus 1.4mm fraction
  • Water recovery using hydro-cyclones and recycle water tank from the minus 1.4mm fractions
  • Flotation of gold and sulphides from the minus 1.4mm (nominal) stream using purpose built flash flotation or similar cells
Gold Fields employs Python technology

Gold Fields South Africa has been working very closely with Gekko’s Technical Team over the last 12 months on several current and future projects. The Gold Fields KDC East 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.

Gekko’s test protocol includes:

  • Pre-screening and gangue rejection
  • HPGR and/or VSI comminution test work
  • Multi-stage crush/grind and gravity recovery analysis
  • Flotation recovery analysis
  • Pre-concentrate upgrade
  • QEMSCAN mineral analysis
The concentrate treatment stage includes:
  • Intensive cyanidation of concentrates to test for amenability to the Gekko ILR technology
  • Conventional CIL tests
  • Regrinding of concentrates
  • Carbon uptake testing
  • Electro-winning testing
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 250tph with the increased throughput allowing Gold Fields to process the waste material at a significantly accelerated rate.

It is the clear objective of both Gekko Systems and Gold Fields Ltd that the upgraded Python flow sheet at KDC be rigorously tested and optimised prior to advancement of the technology on other sites currently undergoing test work.

Gekko Systems specialises in the design, development and distribution of innovative mineral processing equipment and systems with particular focus on gravity separation.

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