Gravitational Concentration

Within the great number of new projects of gold of the world, there are various small projects which exist, in which the cyanidation can not be the best election as the initial process.

The success of the decision depends on the production of gold by unit of invested capital. Especially in the cases in which one disposes of little capital and the project is small, the election to performa gravitational concentration or by flotation can be the most adecuate.including in certain superficial deposits of low law and of a great size, they can sometimes have better results if one uses some type of concentration followed by CIP of the concentrate. On the other hand, the gold of placings has also grown in importance.

Among the important advances in the preconcentration by choosing, which eliminates an important part of the gangue, we can quote the chosen mechanized to base of properties such as reflectivity, color, electromagnetism, conductivity, etc.; or the separators by better densed means, of high capacity. Among the equipment for the gravitational concentration we can analyze the samples.

Interesting advances have been produced in the tables, those of which are fabricated with various superplaced coverings and, principally, in the spirals and the Reichert cones. The spirals are fabricated in two types: for high laws and for low laws. Its capacity varies between 2 and 6 t/h, processing the pulp until 50% of solids. The cones are characterized for their high capacity. They work with 60% of solids. These equipments can be installed in mobile units, this is very advantageous for small operations.

Cimm has mounted demonstrative labours of gravitational concentrations for treating different materials, like for example re-washings of small canals of placings. This plant holds a feeder, a vibratory sifters, a pump and a cyclone AKW to eliminate the lames and to thicken the feeding in a spiral Reichert LG-7. immediately after, the weighed concentrate is re-processed in in a Deister 15S table, which gives a sensitive concentrate of being amalgamated. The capacity of the pilot mobile plant is of 2-3 t/h (19). Cimm possesses, besides that, a Reichert pilot cone, a jig, a separator by dense means and other special concentrators.

Concerning the centrifuge concentrator, this has had a lot of success both, in placers as in other deposits. The centrifuge concentrator Knelson has had important betterings, fabricating it also in small mobile units.