Mineral Gravimetry

The modalities of the putting into movement of the different gravimetric methods according to the way they direct themselves to the minerals if the placer type, for which they constitute the only treatment, or to the other types of minerals of gold by which they intervene as a complement.

The placers are probably the oldest exploited minerals.

The principles used in its treatment are well known from a long time ago: sluices, dormant jig beds, shaking beds, spirals.

The matching used for the recuperation of gold from the placers is well described in Taggart (16) and has been revised recently by Gomez and Martinez (18).

The exploitation of the placers is actually very frequently directed to the craftsmanship scale, and for this the apparatus used know of multiple variations and adaptations of details. These variations, like the selection of the apparatus themselves, are generally dictated by the presentation of the gold in the placers which are frequently found in the pelletmetric narrow borders which is important to be well informed.

Some innovations have appeared recently in the technique of exploitation of the placers: the use of the cones of Reichert, for example, are maintained.

The pits of the sluices and dormant beds are frequently equipped of new materials of the moquette type, which replaces the corduroy textures which were used in times past.

These two innovations allow a better recuperation of gold of weak dimension (less than 100 microns).

In the same way, the growth of the moist agent allows in some cases, avoiding that the fine gold will not float naturally, better concentrate it.