An inverted up-flow separator for the separation and recovery of target minerals, selected from the group consisting of fine and ultra-fine minerals, from a feed including particulate matter which comprises target mineral particles and gangue particles, the inverted up-flow separator including: (a) at least one working fluid inlet; an upper column; a feed inlet, for a feed including particulate matter which comprises target mineral particles and gangue particles, into the upper column; a lower column; a recovered product outlet; the upper column and lower column being in fluid flow communication with each other; a connecting member, connecting the upper column and lower column; and wherein: (b) the feed inlet has a feed outlet, the position at which the feed outlet terminates, in the inverted up-flow separator, being adjustable to optimise the discharge of feed in the inverted up-flow separator, (c) the upper column has a greater diameter than a diameter of the lower column; and (d) the upper column and lower column are configured and dimensioned such that upon introduction of an up-flow working fluid into the lower column, through the at least one working fluid inlet, the particulate matter in the inverted up-flow separator, when filled with fluid, is fluidised thereby imparting a first up-flow velocity (V 1) to the particulate matter in the lower column and a second up-flow velocity (V 2) to the particulate matter in the upper column, wherein the first up-flow velocity (V 1) is greater than the second up-flow velocity (V 2) and wherein the ratio of the first up-flow velocity (V 1) imparted to the particulate matter in the lower column to the second up-flow velocity (V 2) imparted to the particulate matter in the upper column is between 1:0.6 to 1:0.8. (a) at least one working fluid inlet; an upper column; a feed inlet, for a feed including particulate matter which comprises target mineral particles and gangue particles, into the upper column; a lower column; a recovered product outlet; the upper column and lower column being in fluid flow communication with each other; a connecting member, connecting the upper column and lower column; and wherein: (b) the feed inlet has a feed outlet, the position at which the feed outlet terminates, in the inverted up-flow separator, being adjustable to optimise the discharge of feed in the inverted up-flow separator, (c) the upper column has a greater diameter than a diameter of the lower column; and (d) the upper column and lower column are configured and dimensioned such that upon introduction of an up-flow working fluid into the lower column, through the at least one working fluid inlet, the particulate matter in the inverted up-flow separator, when filled with fluid, is fluidised thereby imparting a first up-flow velocity (V 1) to the particulate matter in the lower column and a second up-flow velocity (V 2) to the particulate matter in the upper column, wherein the first up-flow velocity (V 1) is greater than the second up-flow velocity (V 2) and wherein the ratio of the first up-flow velocity (V 1) imparted to the particulate matter in the lower column to the second up-flow velocity (V 2) imparted to the particulate matter in the upper column is between 1:0.6 to 1:0.8.