I managed to get one of these. http://www.ebay.com/itm/111011463348?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2648 It is a combination shaft that supports 3 different companies. I wonder how the ore was segregated at the top? Where there 3 cars available to dump in or were records of output kept and the ore commingled ?