The accompanying photo shows the 4.14m high-bay doors at the top collar of the waste hoist shaft.  The perpendicular cross section of the opening is 3.5m x 4.14m, but the bottom cage cross section is 2.87m x 4.5m (and 4.67m into the plane of the photo).  Depending on actual envelope dimensions and rigging limitations, taller items can be accommodated.  However, tail ropes attached to the underside of the waste conveyance preclude slinging operations for objects which are able to be passed through the doors.  Tall objects (up to 7.6m long) can be slung under the salt shaft conveyance.