Flotation tests were conducted to compare the arsenopyrite depressing effect of MAA with pH control, potassium permanganate and pre-aeration. The recovery and selectivity were optimised by varying the collector and depressant concentration, pH and the effect of copper sulphate addition. It was, found that with MAA, depression of arsenopyrite was possible however, the recovery of pyrite was also adversely affected. To achieve the best separation, the pulp conditions were a pH of 8, 2.14 x 10(-3) mol/l sodium ethyl xanthate and 250 mg/l of MAA depressant. These conditions resulted in an overall arsenopyrite recovery of 25.5% and a pyrite recovery of 62.1%, a decrease in recovery of 63.0% and 7.5%, respectively. (C) 2003 Published by Elsevier Ltd.