Nyrstar is a global multi-metals business, producing significant quantities of zinc and lead as well as other products which include silver, gold and copper. Nyrstar’s Port Pirie smelter is located on the eastern side of the Spencer Gulf in South Australia, approximately 200 kilometres north of Adelaide.
The Port Pirie smelter is an integrated multi-metal blast-furnace smelter and refinery with the flexibility to process a wide range of metals from lead-dominant feedstock. With 670 full-time employees and 110 contractors, this large smelter produces refined lead, silver, zinc, copper and gold.
The operating environment is a particularly aggressive one that exposes equipment and personnel to extremes that include corrosive chemicals, dust, heat and humidity.
Critical to the management of such a large and extreme operation as at Port Pirie, is a reliable automation system. In 2008, Nyrstar’s Port Pirie site celebrated 120 years of operation and Schneider Electric’s Modicon PLC turned 40.
To commemorate this landmark occasion, Nyrstar decided to celebrate by giving their long serving automation platform a face lift. Nyrstar’s automation platform consisted of over 20 Modicon PLCs that had been installed in the 1990s and almost 350 variable speed drives (VSDs).
Nyrstar required a solution that would migrate their automation systems in accordance with their maintenance schedule, downtime and budget. Recognising that availability of spare parts would shorten, or lengthen the timeframe to complete migration, Nyrstar were searching for a supplier who could deliver spare parts and different migration options tailored to their business.
Nyrstar also identified that there was a potential risk of failure as there was limited preventative maintenance for their VSDs. Any solution implemented needed to be able to cope with the site’s harsh conditions, whilst minimising production downtime during project delivery.
Nyrstar were looking for cost-effective methods of preserving their existing hardware and programming investment while extending component life and improving the manufacturing process.
Schneider Electric proposed a solution that would enable Nyrstar to progressively modernise their PLCs with minimum disruption. Modicon PLCs have set the standard for reliability, quality and long-lasting performance for a wide variety of applications.
Partnering with Schneider Electric Services, and implementing new Modicon Quantum PLCs, meant that migrating the automation systems on-site became easier. Nyrstar were able to choose between a complete, phased or partial migration on a case by case basis.
The choice of migration methods, combined with the openness and interoperability of Schneider Electric’s Unity platform allowed Nyrstar to evaluate the scope and cost of each migration project and better manage it to fit their maintenance schedule, downtime and budget.
Having the choice of migration methods allowed Nyrstar to identify the type of upgrade that best suited each unique situation. The site could then tailor a method that met the individual needs while reducing cost, burden and risk, thereby making the project more manageable from a budgetary standpoint.
Nyrstar required the migration to proceed in the shortest possible timeframe, making the availability of spare parts a critical component of the solution. The open-ended commitment from Schneider Electric means that Nyrstar will be able to coordinate directly with Schneider Electric to ensure that parts not yet migrated will still be available.
In conjunction with system integrator GPA Engineering, one of Schneider Electric’s Partners, the PLC migration was completed in 12 months with minimum downtime.
Maarten de Vries, Nyrstar’s senior electrical engineer, says "the comprehensive services provided by Schneider Electric allowed us to progressively migrate our automation platform to suit our business requirements. This enabled us to time the changes so that we could schedule the migration to coincide with planned maintenance downtime".
At the same time that the PLC migration strategy was implemented, Nyrstar chose Schneider Electric to provide a preventative maintenance program for approximately 350 variable speed drives on the Port Pirie site.
These include a number of brands however the majority were Schneider Electric’s PDL drives. The drives servicing would be provided by Schneider Electric’s nationwide support team, with local support delivered out of the Adelaide workshop.
In order to develop a strategy that would address the specific needs of Nyrstar’s Port Pirie smelter, an installed base audit was undertaken to assess the current situation and propose recommendations that would support the life-cycle of the drives equipment.
Following this audit, Schneider Electric’s Drives Servicing team proposed a strategy designed to extend the mean time between failures (MTBF). While the risk of failure is minimised by choosing high quality products and performing regular maintenance, it can never be entirely removed.
It can however be managed. Parts availability or obsolescence can be very costly in the event of breakdown. Downtime can be significantly reduced by being prepared. It is for this reason that Schneider Electric Services documented a detailed spares list for Nyrstar that categorises spares according to their criticality and whether they are required on or off-site.
Nyrstar’s drives maintenance program now includes a spare parts contract that ensues replacement parts are readily available for both current and legacy PDL drives within agreed contractual timeframes; and an upgrade path for ‘same footprint’ changeover.
In addition, a comprehensive on-site training program was implemented to educate Nyrstar’s maintenance personnel. The training addressed various topics including operator training, commissioning, maintenance checks and basic on-site repairs.
The training program delivered by Schneider Electric on-site at Port Pirie has resulted in improved knowledge of Nyrstar’s maintenance personnel. Maintenance personnel have priority access via a toll-free 1300 number, to a team of Schneider Electric experts meaning that most support issues can now be resolved remotely either by phone or e-mail.
All legacy PDL drives can now be serviced and spare parts can be conveniently supplied from Schneider Electric’s Service workshop in Adelaide, approximately 200 kilometres from site. In addition, a range of PDL and Telemecanique drives are available for use as service drives.
These are used by Nyrstar to reduce downtime during breakdowns or for temporary replacements during routine maintenance. On the rare occasion that legacy drives cannot be repaired, Schneider Electric has developed a simple adaptor plate for the installation of an equivalent Altivar drive from Schneider’s current product range.
This adaptor plate is available for the entire PDL legacy drives range, providing a viable solution for migrating legacy drives. Since Nyrstar implemented Schneider Electric’s drives maintenance program, the failure or problem rate has been reduced from high to virtually zero.
This has resulted in cost savings as there has been little need to replace drives due to failure. "We are standardising all new installations here at Port Pirie to Schneider Electric drives because of their superior service provision and class-leading Altivar drives offering," says Nyrstar’s Maarten de Vries. "The maintenance program we have adopted has reduced failure significantly which means our productivity has also improved."
Following the success of the PLC migration and drives maintenance program, Nyrstar are working with Schneider Electric to continue the migration of remaining PLCs when scheduled downtime permits.
In addition, work is underway to replace the obsolete drives with Schneider Electric’s Altivar range of drives.
[Paul Cooper is National Segment Manager Industry Business (Mining, Minerals, Metals) at Schneider Electric.]
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