Oxygen is required for the leaching of gold ores in cyanide solutions. The source of this oxygen demand and the effect of dissolved oxygen concentration on the rate of the process are briefly reviewed._x000D_
A method of measuring the oxygen consumption rate is described and some experimental results reported._x000D_
Fundamental aeration theory and rating of aerators is summarised to show how this type of experimental work provides the basis for full- scale design of aeration equipment.