Placer Gold Mining | Process & Equipment

Placer gold refers to the sand-like gold separated from gold-bearing geological bodies by geological actions such as weathering, denudation, transportation, and deposition. The placer gold mining process mainly includes is mainly divided into two stages, namely preparation operation and ore beneficiation operation.

Placer Gold Preparation Operation

The preparatory work before placer gold beneficiation is not complicated, mainly including crushing &screening and desliming.

（1） Crushing and screening

The crushing operation of placer gold ore is not only to crush the material to a suitable particle size for beneficiation, but also to disintegrate the cemented mud mass contained in the placer gold ore. These cementitious clumps also contain some gold, which, if not disintegrated, will be discarded along with the waste rock during sieving, resulting in the loss of gold.

 The screening operation is to remove the waste rock. The commonly used equipment is a dewatering screen, which can not only improve the screening efficiency, but also further dissolve the mud mass.

(2) Desliming

The gold particle size of placer gold is small, and the gold particles smaller than 0.1 mm are called floating gold, which is difficult to recover. However, the sludge of the same particle size as the floating gold interferes with the beneficiation process and affects the beneficiation effect, so the sludge under 0.1 mm is generally removed.

Placer Gold Beneficiation Operation

In the continuous exploration and practice, it has been proved that the gravity separation method is an economical and effective method to deal with placer gold.

According to the particle size of gold in placer gold, different gravity separation equipment can be selected for separation, or several kinds of equipment can be used in combination. Commonly used placer gold gravity separation equipment includes jig, shaking table, spiral chute, centrifugal separator  and so on.

(1) Jig machine: The jig machine has a large processing capacity and a high recovery rate. It can handle fine-grained placer gold and can be used for roughing and beneficiation of placer gold;

(2) Shaking table: The sorting size of the shaking table is fine, but the processing capacity is small, and the floor area is large. It is suitable for selecting the rough concentrate of placer gold;

(3) Spiral chute: The spiral chute has a large processing capacity, but the recovery rate is not high, and the loss of fine-grained gold is large. When the content of fine-grained and fine-grained gold in the placer gold ore is small, the spiral chute can be selected;

(4) Centrifugal Separator: Centrifugal Separator has high recovery rate for fine-grained placer gold ore and large processing capacity, but requires high water pressure and consumes large amount of water.

The beneficiation process and equipment of placer gold ore need to be selected according to the particle size and properties of gold in placer gold ore, so it is recommended to carry out processing test to determine the best process flow of placer gold ore beneficiation.