A telescopic boom conveyor apparatus including a boom that carries a conveyor, a support structure for the boom, a rear pivot joint that connects a rear end of the boom to the support structure , a pivot drive that controls pivoting movement of the boom about the rear pivot joint , an operator cage attached by a front pivot joint to a front end of the boom; wherein the boom conveyor includes a rear boom section that is connected by the rear pivot joint to the support structure , and a front boom section that is connected by the front pivot joint to the operator cage , wherein the front and rear boom sections are telescopically adjustable to adjust the length of the boom conveyor ; characterised by a levelling system that controls rotation of the operator cage about the front pivot joint , wherein the levelling system includes a flexible cord that is attached to the operator cage and extends from the cage towards the rear end of the boom, and a level adjusting device that is attached to the support structure adjacent the rear end of the boom and engages an adjusting portion of the cord , whereby during pivoting movement of the boom the level adjusting device controls longitudinal movement of the cord relative to the boom so as to apply a levelling adjustment to the operator cage ; wherein the levelling system includes a compensating mechanism that compensates for changes in the length of the boom conveyor ; wherein the compensating mechanism includes a first compensating guide element located towards a rear end of the front boom section , a second compensating guide element located towards a front end of the rear boom section ; and wherein the cord includes a front portion that extends from the operator cage to the first compensating guide element , an intermediate portion that extends from the first compensating guide element to the second compensating guide element , a rear portion that extends from the second compensating guide element to a return mechanism that is located towards the rear end of the boom conveyer, and a return portion that extends forwards from the return mechanism and is attached to the front boom section . characterised by a levelling system that controls rotation of the operator cage about the front pivot joint , wherein the levelling system includes a flexible cord that is attached to the operator cage and extends from the cage towards the rear end of the boom, and a level adjusting device that is attached to the support structure adjacent the rear end of the boom and engages an adjusting portion of the cord , whereby during pivoting movement of the boom the level adjusting device controls longitudinal movement of the cord relative to the boom so as to apply a levelling adjustment to the operator cage ; wherein the levelling system includes a compensating mechanism that compensates for changes in the length of the boom conveyor ; wherein the compensating mechanism includes a first compensating guide element located towards a rear end of the front boom section , a second compensating guide element located towards a front end of the rear boom section ; and wherein the cord includes a front portion that extends from the operator cage to the first compensating guide element , an intermediate portion that extends from the first compensating guide element to the second compensating guide element , a rear portion that extends from the second compensating guide element to a return mechanism that is located towards the rear end of the boom conveyer, and a return portion that extends forwards from the return mechanism and is attached to the front boom section . <EOS>