Average blocks now contain 3 million tonnes of raw coal, as opposed to the once standard 1.5Mt, and future projections suggest 9Mt blocks may not be that far off. While in the past longwall equipment was overhauled based on the tonnages mined in a block, Neilson suggests that: “Our thinking and goals must now focus on best practice operating life, based on facts and data not a 3 Mt block of coal.”
The ultimate aim is to extend service life to match the mining system, so that equipment can reliably mine 10Mt blocks.
According to Neilson a mid-face change of core componentry can cost an operator $5-$10 million in lost production. He said Joy’s vision for some years has focused on “ Life Cycle Management Principles” to reduce overall cost per tonne over the life cycle of the equipment and reduce or eliminate in-service failure.
An important key to achieving this was to invest more time and effort in the pro-active/predictive phase of the equipment life cycle using the tools of rigorous condition monitoring and analysis. Neilson points out that while condition monitoring may deliver much information it is not always used to the best effect or adequately analysed. Comparing findings at the point of rebuild with historical data, and in -service condition monitoring builds a picture of component life.
He called for greater openness and partnershiping between OEMs and operators because, “Without trust, shared information and an understanding of relative values, the notion of continuous improvement becomes just another motherhood statement.”
A measure of continuous improvement is new standard, ISO9001:2000, of which Joy is one of a few certified companies in Australia.
“The key tenant is improve continuously and prove you are doing it,” Neilson said.
Both operators and OEMs could do a better job of moving from a reactive approach to machine maintenance to a more predictive approach, with an estimated 50% of activity currently targeted at the reactive maintenance and only 5% of energy directed at the predictive end. Neilson conceded that this is difficult to achieve as reacting to a failure is a lot easier than identifying a potential failure.
A new ‘step-change’ technology in rebuilds is use of CMM (co-ordinate measuring machine) technology, developed out of the aerospace industry. Using sophisticated software, the machine checks that key dimensions on critical components conform to OE specifications. While Joy has had the technology for a few years the company is now using it systematically to check critical components in all Joy equipment rebuilds, such as on a shearer’s ranging arm.
CMM creates a picture of component life under defined operating conditions and allows rigorous inspection of highly stressed components. Results are achieved in a tenth of the time at ten times the accuracy of other types of manual inspections.
To maximise the benefits from these types of technologies Neilson emphasised again the importance of building trust between the operator and the OEM and a shift in thinking about these relationships.
Neilson said the outcomes would be a reduction or elimination of failures in service. Operating cost would be reduced with component overhaul based on its condition.
“This ultimately means a lower cost per tonne over the life cycle of the equipment,” Neilson concluded.
