Gravity Separation

  • Coal
  • Gold - alluvial or free
  • Mineral sands - rutile, zircon, ilmenite
  • Tungsten
  • Silica sand
  • Chromite
  • Tin
  • Iron
  • Platinum
  • Carbon - chips or slime
  • Aluminasilicate
  • Soil cleaning
  • Sulphides

The feed box is back-fed with a tangential pulp outlet to ensure maximum use of the spiral separating surface. Product splitters are located in the product box and at times on the helix to divide the stream into concentrate, middling and tailing fractions. .


The spiral is a low cost gravity separator designed to treat pulp
with a mineral or coal content in
the 1 - 50% range by weight.

Different models with 1, 2 or 3
helixes per column and with any number of turns per helix are
available depending on the
specific application.

Test facilities are available to establish design criteria.

Trial units can be provided
subject to availability.


The spiral can be used as a rougher, a midlings retreat, a scavenger or as a cleaner or recleaner unit depending on the design of the flowsheet.


  • No washwater is required
  • Concentrate handling is via visible open channels rather than slots, pipes or galleries
  • Simple operation with spirals requiring minimum adjustment
  • An aluminium support column for longer spirals ensures perfect rigidity
  • Cascade product boxes minimise launder plumbing
  • Efficiency maintained under variable feed conditions


  • Multistart spirals have the operational advantage of common cutter assemblies
  • The helix is constructed from epoxy and glass with a polyurethane wear surface
  • Feed and product boxes are cast polyurethane

Minerals up to 2TPH dry solids
Coal up to 4.5 TPH dry solids per start


Minerals 0.075mm to 1mm
Coal 0.1mm to 2.5mm

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