News Center

Industry News

Company News

Home page

2026

The working principle of a gold dredge

A gold‑panning vessel, also known as a gold‑mining vessel, is an integrated mining and processing unit mounted on an engineering‑type flat‑bottomed barge and kept afloat on the water. It is a mechanical device used to extract placer gold from riverbeds.

A gold‑panning vessel, also known as a gold‑extraction vessel, is an integrated mining and processing unit mounted on a flat‑bottomed engineering barge and kept afloat on the water. It is a mechanical device used to recover placer gold from riverbeds. Its basic operating principle involves using an excavation system to scoop river sand from the submerged riverbed; a screening system then separates out larger stones—typically exceeding 10 mm—and disposes of them via a tailings discharge system, while finer sand particles smaller than the screen openings are conveyed to the gold‑panning system. Within this system, leveraging the difference in specific gravity between sand and gold, the heavier gold settles under the impact of water flow and is recovered, whereas the lighter sand and other tailings are carried away with the effluent.
The dredging system of a bucket‑type gold‑washing vessel consists of buckets, a chain, a drive sprocket, and a bucket carrier (the underwater boom), among other components. During operation, a reducer drives the drive sprocket, which in turn rotates the bucket chain, lifting submerged sand and ore to the working platform and discharging it into a screening system—such as a rotary screen or a vibrating screen—for sand–stone separation. Under the scouring action of water supplied by the water‑supply system, fine sand flows onto a gold‑concentrating bed—such as a fixed sluice or an agitated sluice—lined with enrichment media like felt, gold‑collecting grass, or gold‑settling cloth. Because gold has a much higher density than sand, the water carries away the sand particles while the gold grains remain on the enrichment medium, thus achieving “gold panning within the sand.” The separated tailings are discharged via a chute or a conveyor belt, depending on the tailings‑removal system.
Suction‑type gold‑mining vessels use a diesel‑powered sand pump to extract sand. Their operating principle involves drawing underwater sand deposits upward as a sand–water mixture, with a typical solids concentration of about 25%–30%. The primary suction methods are cutter‑suction or jet‑suction. The extracted sand slurry first enters a buffer tank for pressure reduction and is then evenly fed into the gold‑recovery system, such as a peristaltic gold‑washing chute. Within the chute, heavy metals like gold, due to their higher specific gravity, remain on the sluice’s gold‑catching mat, while lighter sand and silt are carried by the water flow into the tailings bin and ultimately discharged to the shore via a tailings pump. Depending on the particle size of the placer gold, suction‑type dredgers can be equipped with various gold‑recovery processes, including sluices, centrifuges, or agitated chutes.
In addition to bucket‑type and suction‑type systems, gold‑mining vessels also employ jet‑suction and other types of excavation systems. The selection of gold‑recovery systems is equally diverse, encompassing fixed sluice boxes with gold‑bearing mats, agitated sluice boxes, automated washing‑and‑classification units paired with centrifugal concentrators, spiral sluices, shaking tables, and more. At present, agitated sluice boxes and automated washing‑and‑classification units combined with water‑jacketed centrifugal concentrators are widely used due to their simple construction, high throughput, high concentration ratios (up to 1000:1), and excellent recovery rates (exceeding 90%). As for the screening system, depending on the rock‑content and particle size of the raw ore, one may opt for a rotary screen, a flat screen, or omit screening altogether.

Gold mining equipment

The process flow of a gold dredger

Gold mining equipment

The process flow of a gold dredger