Hydraulic traps are employed for performing the prior separation of coarse gold particles such as grains and nuggets in order to obviate the need for their subsequent milling, amalgamation or leaching. Hydraulic traps are also widely employed for recovering amalgam and mercury downstream of amalgamating stages (e.g. stamp mills or amalgamating plates). Hydraulic traps differ according to design and function. In this way, some hydraulic traps are designed for counterflow of water. This type of equipment works like a small, artificial settling tank placed in the main flow of slurry, but only allows heavy particles to settle out. The counterflow of water keeps the sedimentation chamber largely free of lighter particles. In that sense, a hydraulic coarse gold trap is comparable to a single section with clear water counterflow.
The settled gold concentrate can be recovered with the trap in operation by opening a discharge valve at the bottom of the trap. In some designs, the slurry enters through an inlet pipe and is forced to change directions a number of times before escaping and gold, quicksilver or amalgam separates and settles to the bottom. This makes such systems similar to round or lamellar thickeners. The design is simple and all components such as ball valves, pipe sections, fitting or steel sheets can be obtained easily.
Hydraulic Trap