Moving Quickly Into Production
Multi Gravity Seperator Process Technology
Traditionally, equipment for Coltan mining is very similar to gold mining; gravity based and allowing significant recovery for particles larger than 300 microns, with smaller particles being washed away New technology, currently applied in tin, gold and coltan mining, has been proven to recover particles smaller than 100 microns. Tests of material originating from Issia Project confirmed a significant part the coltan particles in the concession are between 100-200 microns.
A sample was sent to the equipment provider for analysis, so that calibration and optimisation of the planned process system was undertaken in order to recover 90-95% of the coltan from the ore.
The design of the plant has been especially developed for the recovery of Coltan and is based on MGS which operates on a similar principle to a shaking table to separate and upgrade very fine materials via a subtle centrifugal force which simulates enhanced gravity, pins heavier materials to the wall of the drum that are then dragged forward by scraper blades, while lighter tailings are agitated by the shaking motion and washed away.
The MGS can be used as a primary separator of fine materials, scavenging tailings and middlings from spirals or shaking tables. Alternatively it can be used in two stages to maximise recovery and grade. The MGS will function satisfactorily with materials up to 500 microns, but it works exceptionally well where there is a narrow size band of material below 100 microns.
The benefits of using a gravity separation system in a gravity circuit are typically:
- Delivers very high grade recovery from fine and ultrafine material
- Sustainable, chemical free processing
- Suitable for concentrating many valuable metal bearing ores
- Self regulating and able to cope with significant changes in material grade without losses
- Ability to cope with changes in feed pulp density by adjusting wash water levels.
Design, purchase, construction and commissioning of the system (at a capacity of 30 tonnes per hour) is expected to take approximately six months and cost approximately $8 million
We will produce a Tantalum concentrate powder containing 55% Ta2O5. This sample product will be drummed and shipped for export to customers for sampling via the Port of Abidjan
Process Plant Flow
1st stage: JIG separation
Ore is mixed with water within the trommel in order to wash away organic material and waste, as well as to sort the material dependent on size. Bigger particles (150mm-24mm) are introduced into an automatic colour sorting machine which separates the particles into 4 groups; coltan, aggregates, quartz and mix material. The mix material is re-introduced into the processor. All particles smaller than 24mm but bigger than 1.86mm are separated by JIG, which removes the coltan to a storage tank. The middle sizes are crushed and re-introduced into the trommel for processing. All particles smaller than 1.86mm continue to the second separation phase.
2nd stage: Spiral separation
All material smaller than 1.86mm enters the spiral separation phase, while all particles smaller than 105mm continue to the 3rd separation phase. For better performance an agitator is used to add water and get to the optimal mix prior to introduction into the spirals. In the Spiral stage material is separated into coltan, light and middling’s material whereas Coltan is taken to storage, Middling’s and lights are crushed in a 100 μm crusher. And reintroduce into the process.
3rd stage: Mining Gravity Separation (MGS)
Particles smaller than 105mm are introduced into the gravity separation phase. An agitator is used again to improve the concentration and obtain optimal results in this high technology separation system. At this stage particles from 105μm to 0μm are sorted and all coltan is recovered and sent to the coltan storage facility. Tailings are sent to tailing storage and all particles larger than 63μm are crushed and reintroduced into the system. Water is filtered and reintroduce into the system