A coarse-fraction concentration method used in milling pebble phosphate in which conditioned feed at 70% to 75% solids is placed on a flat conveyor belt traveling at a rate of about 75 ft/min (22.9 m/min). Water sprayed on the surface of the pulp aerates the pulp, causing agglomerates of phosphate particles to float to the side of the belt for removal. The silica fraction travels the length of the belt and is permitted to flow off the opposite end. Baffles are positioned at appropriate points along the belt to stir the material so that trapped phosphate particles are given an opportunity to float. Concentrate from the first belts or rougher operation is cleaned on a second belt for further silica removal. Tailings from the cleaner belt are recycled to the rougher circuit.