Analysis of Breakages of Longwall Powered Supports - Why Cycles Testing Does Not Guarantee Happiness

In recent years, SUEK has suffered serious breakages of four sets of powered supports, including caving shields and the attachment of the powered supports to the AFC. All of these supports had undergone prototype testing prior to manufacture, but the design errors were not manifested under conventional test conditions. Breakages occurred underground where it is not possible to instrument the equipment, and where reliable data is hard to obtain by visual means. This paper describes the "forensic engineering" that led to the identification of the root cause of the damage, and the ways in which this was rectified. Two new sets of supports have also undergone design changes to prevent the same risk of damage. The solutions are simple, but developing this knowledge has cost a lot.