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For a major industrial operation like Carter Holt Harvey’s Tasman Mill, shutting down operations even for a day is expensive. This means that making the most of the shutdown period, and making sure that shutdown programmes run to schedule, is critical.

To achieve these objectives mill management works closely with industrial services firms like Intergroup, which prepare and specially deploy teams of staff and equipment for the duration of the shutdown. The team’s performance in earlier years won it much greater responsibility this year.

Intergroup wins key maintenance responsibility

For Carter Holt Harvey’s Tasman mill, in Kawerau, the annual shutdown is a chance to do all the things that can’t be done while the mill is in operation. This includes essential maintenance and upgrade work.

In previous years Carter Holt Harvey contracted three industrial services firms to carry out a range of maintenance activities.

This year, Intergroup was awarded a wide ranging maintenance contract. Intergroup mobilised up to 90 personnel, and up to 20 units of plant, from depots all over the North Island to meet the full scope of work. Our crews worked flat out for two weeks, on 24/7 rotating shifts, to complete the schedule of activities within the allocated time.

Multiple activities packed into the shutdown programme

Since a full mill shutdown means lost production, mill management tries to pack as many maintenance and upgrade activities as possible into the programme.

This means that numerous service providers and hundreds of contractor staff mobilise on site over a very short and intense period of activity. The opportunity for health and safety incidents is high, while the potential for work clashes, which may result in expensive delays, is ever present.

Careful planning, staff with high health and safety awareness and training, and close communication amongst all parties is crucial to maintaining a safe work site.

Wide range of activities

The works Intergroup handled included High Pressure (HP) water blasting, Ultra High Pressure (UHP) water blasting at 40,000psi and vacuum loading. Maintenance was carried out on a range of plant equipment including evaporators, boilers, kilns, continuous digester towers and oil tanks.

HP water blasting was used for corrosion control and surface cleaning.

UHP water blasting was required to cut out the extremely hard crystallised lime slag in the boiler hearths and to take steelwork in pressure vessels back to the original profile around welds to enable non-destructive testing (NDT). The rotary lime kilns were cleaned out using vacuum loading.

Planning for the unexpected

Running the programme efficiently and safely requires extensive pre-shut planning. To make sure all potential issues were considered and addressed, Intergroup managers in Kawerau worked closely with Carter Holt Harvey managers in the weeks running up to the shut.

This planning time was well spent, as programmed work activities ran smoothly throughout. However, as with any shutdown, once production ceased numerous additional activities came to light. Intergroup, shouldered all of the additional work.

In fact the scope of shutdown work increased by about 20% over what was identified in advance.

As Intergroup had planned well and was well resourced, all of the extra activities were handled within the programme, but it took some juggling on the part of management on site, close day by day monitoring of work progress and close communication with plant management, to make sure that no work was left undone.

Relief at a job well done

Despite facing numerous challenges, especially in scope expansion, the shutdown maintenance works were completed successfully and the plant restarted on time. The teams get to have a well-earned break, while management starts planning for the next shutdown.