Open Cut » Maintenance & Equipment
Metacoustics has been involved in a number of research projects jointly funded by Metacoustics (71.5%) and ACARP (28.5%) over the past 6 years. One project has been the adaptation of acoustic emission techniques for use in monitoring the integrity of dragline booms. Now that the research project work is ending, Metacoustics is in a position to offer a monitoring system for use on all mining machines, and specifically on draglines. The research project aims basically were to prove that the technique was adaptable to draglines and to design suitable equipment and develop reliable analysis techniques for detected data. It was never our mandate to provide a service during these research projects, however we are now in a position to offer a wide range of monitoring services.
Acoustic emission is a passive listening technology, so sensitive that it can detect atom/dislocation/crack movements in structures, and at the same time discriminate between material deformation, cracking and process/operating noise. Due to the special problems and difficulties that we recognised during this project, a totally new concept in monitoring has been developed, using acoustic emission techniques but overcoming most of the localised/on-site problems associated with sophisticated on-line monitoring of equipment in a working mine site environment.
The new instrument can monitor a number of locations and intensively monitor selected zones/welds. The final analysis provides an indication of the Structural Integrity (SI) and associated trends of the zone monitored. Any damage will show up as a loss of SI, and as that computed value of SI approaches a predetermined value, repair can be planned in advance of catastrophic failure.
The research work has indicated that many zones on a dragline boom and mast require monitoring. We recommend that each dragline project be customised to include both general and concentrated monitoring zones, the latter governed by past failure experience and operating techniques. The results of the monitoring program will identify zones of excessive/abnormal wear and cracking which can be linked to operating techniques and pre-excavation blasting efficiency, and provide information for planned maintenance scheduling. An added advantage of this technique is that presently unknown defect areas can be identified and repaired, and known defect areas which are less affected by plant operations can be "watched" and repaired on schedule, rather than in panic or associated with failure.
The report details investigation and advances made in the monitoring of dragline booms using advanced acoustic techniques.