log-washer

[img_assist|nid=11973|title=|desc=|link=none|align=right|width=151|height=158]A long water tank set at a slope, in which one or two shafts, or logs, fitted with paddles set helically rotate. The feed is introduced at the lower end of the tank, the paddles break it up and subject it to a tumbling action; dirty water and fines are discharged at the lower end and washed aggregate at the upper end. These washers are used where there is conglomerate or a high proportion of clay among the gravel.