Oct 29, 2018 Trommels are effective on any type of placer deposit where the gold is mixed in with loose gravels, sands, and clay. It should be noted that many of the best deposits that are mined by large operations are exposed bench deposits and tertiary river gravels.Many of these areas are now high and dry above the current river channel, but they can still be mined Overview. Vibrating sluice box ( pulsating sluice ) is a new type of placer gold mining equipment developed on the ordinary fixed gold sluice box. The vibrating sluice box is a gravity separation machine, mainly used for the placer gold mines. It combines the advantages of fixed chutes and jigs, over the shortcomings of silting-up, harden, has ... The fineness of the placer gold is usually 850-900, and the average specific gravity is 17.5-18.0. And our JXSC Mine Machinery has rich experience for design, control, and optimization of such a complex process for nearly 2 decades, with our solution, high recovery, high profit and low cyanide concentrations can be achieved simultaneously.