Crusher exceeds expectations at Hunua

The Metso HP4 crusher was supplied by Mimico and installed during the Easter shutdown period this year.

Winstone Aggregates national manufacturing manager Jason Lowe said the new generation crusher had achieved or exceeded all the performance targets set by the company. He said the original tertiary crusher was still running well, but struggled to adapt to a shift in market requirements.

?We found that more of our customers, especially the ready mix concrete and asphalt customers, were tending to go with smaller chip sizes. So we were seeing increased demand, especially for a 10mm chip.

?Our existing crusher was making too much 19mm chips and we had to re-circulate the 19mm to get more 10mm. As a result of this extra load in the tertiary circuit, our throughput was limited, the crusher was working at full capacity and therefore the overall crushing circuit was not as efficient as we wanted,? Jason said.

The crusher was operating 18 hours a day,six days a week, with the rest of the time required for preventative maintenance, givingminimal flexibility to adjust to market demands.

Winstone Aggregates has utilised Metso?s Bruno process simulation software for many years and staff began modelling the existing process using Bruno about three years ago. They modelled the existing process and calibrated it against actual measured inputs and outputs. Then they produced a number of Bruno models incorporating the Metso HP4, liaising with Mimico?s process equipment engineer, David McCaffrey, and Metso in Australia.

Jason Lowe said the new generation HP4 was the only crusher seriously considered. For a start, the HP4?s compact nature meant it was the only viable crusher that could fit the space vacated by the existing tertiary crusher. ?And it was also the only crusher I had confidence in to give us the advantages we needed,? Jason said. ?If the HP4 had not been available, we would have most likely continued with what we had.?

The crusher was delivered within two weeksof purchase. Excellent planning meant it wasinstalled over a five-day Easter shutdown period and was operational for the scheduledplant restart. The crusher met all of its agreedperformance targets, and Metso?s performanceguarantee testing was conducted, completed and signed off on the same day.

?We found Mimico were extremely flexible in the range of purchase options available, and their back-up was first class. I could tell straightaway that Mimico were as excited and committed to this project as we were and that gave me additional confidence that the project would be a success,? Jason said. ?For example, we had their top service technician dedicated to the project before, during, and for two weeks after installation, to ensure there were no issues.?  

Winstone Aggregates has also agreed to a parts supply agreement with Mimico, meaning that the service and aftercare of the HP4 will continue for at least five years.

Production improvements measured as partof the Metso performance guarantee exceededexpectations, being better than the Bruno predicted improvements that were as follows:
Tertiary throughput: +22%
Premium All Passing (PAP): +19%
10mm: +31%

Jason Lowe stated that the improvements meant the tertiary plant could now do greater tonnage in fewer hours, giving Hunua the capacity to increase production to meet market demand. It is a benefit they have not been slow to take advantage of.

?We have already taken on contracts requiring significant volumes of 10mm concrete chip because of the production improvements,? he said. ?Without installing the HP4, we would not have been able to take on that work.?

Apart from improved crushing performance, the HP4 features thicker liners that are replaced less frequently. Changing liners also requires less labour and downtime because they do not require backing material. The Winstone Aggregates HP4 was also supplied with the advanced automation package that displays the liner wear rate, crusher settings and key operating parameters, ensuring optimal performance and timing of scheduled maintenance to maximise crusher uptime.

Ironically, Winstone Aggregates began justifying the HP4 purchase based on extra crushing capacity and projected growth. When the recession bit, the justification wasrecalculated on improved crushing efficiencies. Either way, the HP4 measured up.

Source: Metso

Leave a Reply

Send this to a friend