Basic Principles of Gravimetrical Separation & Concentration of Alluvial Gold
This consists in separating the mineralized particles of different specific weights, generally by means of water or currents of air.
In a homogenous paste or pulp of particles which are less than ½”, for the optimum recuperation, one must consider various aspects:
1. Specific gravity;
2. Shape and size of the particles;
3. Type of material, existence of clay, among others.
Types of Gravimetric Separators
Rail sluices.
They are built of wood, iron irons, fiberglass with structural armor.
Its dimensions vary according to work systems:
- Handcraft: 0.85 x 4.50 x 0.15; rifles 3/8” to 0.30 m.
- Mechanized: 2.85 x 7.00 x 0.30; rifles 1” to 0.30 m.
- Fines %: 25%
- Pulp density: 25%
- Gravel density: 1.5 to 2.0
- Auriferous gravel weight before being processed in slues canal 2,170 k/m3
- Weight processed gravel higher than ½” 1,953 k/m3
- Weight processed gravel lower than ½” 2,035 k/m3
a) Advantages
The separation works in sluices have the following advantages:
- Minimal supervision
- You can treat volumes from 10 to 1,000 m3/day
- Very low initial costs.
- It doesn’t require maintenance.
b) Disadvantages
- One does not recover the fine particles of laminar gold; one loses between 20 or 30%.
- One accumulates and reaches light materials, it requires periodic control.
- For washing processes you would require a higher volume of water.
- Periodic change of yute arpillera.
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