cage d'extraction

CONT: The approximate weight of a steel cage is 1 1/2 times that of the coal it carries, or about equal to the weight of the coal and the mine cars. Cages are usually designed to take one or two cars per deck and may be single or multi-decked. Where multidecked cages are used, simultaneous or consecutive discharge of decks can be employed. The modern trend is towards consecutive decking with power-operated cage unloading equipment. Cages can be either steel, composite or all-alloy construction. An all-alloy cage is about half the weight of its all-steel equivalent. The cage is suspended from bridle chains which in turn are attached to the cappel of the winding rope. Normally there are two cages in simultaneous operation in the shaft and travelling in opposite directions.