An apparatus for mixing tank contents including sedimentary material is disclosed. The apparatus includes an agitator connected to a support including a plurality of detachable sections. The apparatus further includes a frame adjacent an opening in a top of the tank. The apparatus also includes an actuatable connector for interconnecting the frame to the support. The connector is configured to be actuated in order to lift a first portion of the support above the frame while a second portion of the support below the frame is maintained, to thereby cause a gap between the first portion and the second portion enabling at least one of the detachable sections to be inserted into the gap. The apparatus also includes at least one actuator for causing the connector to lift the first portion in order to cause the gap, and for lowering the first portion and the second portion.