. The classifier consists of a zig-zag column through which passes an upward moving air current. Material fed into the column is separated into a coarse, granular, higher density fraction that falls through the column and a finer-grained, flakier, less-dense fraction that is entrained. in- the upward moving air current. Initially designed to separate chiefly on particle-size it can be used to separate pre-sized material on the basis of particle-shape. Hence its use in the separation of mica from feldspar and quartz in this study. The separation conditions varied with particle-size. A higher airflow rate was required to remove mica from coarser grained material. For, exam3ple, a rate of 32 m3 per hour was required for the 4+2.8 mm size fraction whereas only
17 m per hour was required for the 1 mm +500 gm size fraction.