Structural failures on mobile materials handling equipment

Abstract

Bulk materials handling systems are extensively used within the mining and minerals industry. Due to the nature of the mining environment, the support structures for these systems are often exposed to special and/or accidental loading conditions. This unfortunately leads to a fairly high incidence of structural damage or failure being experienced within the mining industry, notwithstanding design compliance with appropriate standards. Over the past few decades reputable mining companies have acknowledged the necessity for more conservative structural designs and this has led to the development of design rules for permanent structures which are used in conjunction with national and international design standards. The design of mobile continuous bulk handling equipment is governed internationally by the ISO 5049-1 (1994) Standard, except in Australia where AS 4324-1 (1995) is generally utilised. The study investigates a number of catastrophic failures of mobile bulk materials handling (BMH) equipment to identify the typical root causes and their complex interaction in these disastrous events. A retrospective view is taken of the processes followed during the investigation of the main case study to develop a methodology for future failure investigations. Brief case studies are made to demonstrate the shortcomings of the ISO 5049-1 (1994) Standard, which currently provides no rules or guidelines for machine protection systems. The aim of the study is ultimately to improve structural safety on future mobile BMH equipment designs, which does not necessarily imply a more conservative design approach, but rather that design loads and conditions be correctly assessed. The revision of ISO 5049-1 (1994) is subsequently proposed to provide specific rules and guidelines pertaining to machine protection systems. Other focus areas for consideration are also covered. It is furthermore recommended that the structural design engineer should play a more prominent role during the final acceptance of mobile BMH equipment and handover to the owner. A systems design approach integrating the respective engineering disciplines and based on a comprehensive risk assessment, is required.