Gold Vibrating or Trommel Screen

A vibrating screen or a trommel screen can be used for classifying the material to go over the rag plant. Where there is quite a bit of large pebbles, a trommel screen is better, for it is more rugged and will stand up better. With finer material, a vibrating screen can be used. On most placers with fine gold a ¼ or 3/8 mesh screen is normally used. The fines will go to the rag plant and the oversize will come over the emancipation end of the screen into a by pass chute to waste. The massive material must be handling, so the screen should be elevated so that a stock pile can accumulate and be moved wit a loader, dozer or a concentrate.

The rag plant or sluice box is 4 to 6 ft. wide and 35 to 40 ft. long. It has inside--outside carpet in the base of the sluice with riffles on top of the carpet to grab and save the fine gold. A few types of riffles can be used, punched plate 3x3 x3/16 with 1 ¼ “x1 ¼ square openings punched out works very well. Riffles made of 3/8 rebar welded into 3 by 3 sections, with 1’ -1 ½ spacing can be used. There are also some other kind of riffles which can be used. It is extremely important that the riffle plates fit tight beside the carpet. This is done by using ½ equipment bolts sticking up about 3 ½ and pending through the base side of the sluice box. Bolts are join into place with head of bolt on the below side sluice box. Nuts are turn on to bolt and tie down tightened to keep riffles from touching and held tight against carpet. Pieces can be used among nut and tie down to hold tie down against riffles.

Tie down plates are flat steel plates ¼ “ x 3 x 12” long. They are slotted to slip over bolt on top of riffle plate, and are tightened by screwing down nut on bolt, or by pouring wedge tight among nut and tie down plate.