A sluice including an upper channel that includes a material deck and a tilted classification screen. Below the classification screen is a lower cavity located between two longitudinally aligned plenums located under the upper channel. Each plenum includes a front opening and a rear opening and an interior sidewall. Extending between the plenums is a floor plate. Fluidization holes are formed on each interior sidewall. During use, the sluice is positioned in a stream so water flows simultaneously over the upper channel and the through the front openings of the plenums. Water flowing over the upper channel separates mined material placed on the material deck so that small particles fall through the classification screen. The water entering the front openings of the two plenums flows through the plenums and partially exits through the fluidization holes and sprays over the small particles deposited in the lower cavity further separating the fine gold particles from the small particles.