Case History: Refined Maintenance
By Carroll McCormick
A metals refinery can be one of the harshest environments in industry for both man and machine. Yet there are exceptions to this fire-and-brimstone image, such as the scene at Noranda's Canadian Coppe...
A metals refinery can be one of the harshest environments in industry for both man and machine. Yet there are exceptions to this fire-and-brimstone image, such as the scene at Noranda’s Canadian Copper Refinery (CCR) in Montreal, Que.
Rolling almost silently on steel wheels down a 200-m-long long bay, cameras mounted on a bay carrier precisely guide the delivery of a 16,000-kg load of copper anodes to a percolating cell of sulphuric acid. A sole operator, almost lost in the vast space, supervises the automated process.
This scene is possible because the equipment is under the control of a wireless computer automation system that includes seven Hewlett Packard server computers.
However, the operation is far more challenging than meets the eye: This delivery system and 24 other major equipment systems — all part of new installations at Noranda’s CCR facility — are demanding a new level of finesse from the company’s maintenance personnel.
Noranda carried out its permanent cathode modernization project, as it is known, between 1997 and 2000, spending $126 million to upgrade and automate the electrolysis technology and handling equipment in its copper refining operations.
Maintenance personnel closely followed the manufacture of the equipment — most of it first generation — from design to site acceptance testing, and received extensive training on the equipment at the same time.
“All of the new equipment is radio-controlled,” says Yves Beaudry, the reliability superintendent at CCR. “It is big, precision equipment — hands-off. All this precision for big equipment is a challenge. There is no more ‘good enough.'”
There is much more than just copper refining going on under CCR’s many roofs and the over one million sq ft of floor space, but in terms of tonnage and equipment, copper is the main deal.
The Noranda facility receives 99 per cent pure copper from its mills and from clients, and improves its purity to 99.99 per cent. The copper to be refined arrives at CCR as plates (called anodes) about one metre on a side and a few centimetres thick. The anodes are put into cells of heated sulphuric acid charged with a 23,500-ampere current. A chemical process, electrolysis, makes the copper migrate through the acid on to steel sheets (cathodes). The resulting copper deposits are now 99.99 per cent pure.
Impurities such as gold, silver, selenium and tellurium fall to the bottom of the cells and are recovered and refined separately.
CCR is the second-largest custom smelter in the world, and in 2001 produced 323,000 tonnes of copper cathodes, 1.2 million ounces of gold, 43 million ounces of silver, and other byproducts.
CCR refines the copper in two tank houses, one 90 m wide by 200 m long, the other 125 m by 200 m. Automated carriers deliver anodes to hundreds of acid-filled cells in the tank houses, and take away the cathodes and the cannibalized remains of the anodes.
The cathodes are moved to a complex of automated equipment, which loosens and strips the copper sheets from the stainless steel and packs them for shipment to Noranda’s clients.
Each mechanical player in this game of pass-the-copper is a highly-complex, software-driven system. “The complexity of the transporter system is such that we have three electrical engineers and one mechanical engineer [to run it],” says Claude Belanger, CCR’s superintendent of electrical and instrumentation maintenance.
The refinery’s 6,000 pieces of equipment are on file in an Indus MPAC (SQL version) maintenance system. Maintaining this equipment occupies about 135 maintenance workers, including 95 mechanics and 40 electro-technicians and instrumentation specialists. There are also some 20 planners and supervisors and four maintenance engineers on staff. The annual maintenance budget is $17 million and the refinery stocks $9-million worth of spare parts.
CCR has 3,400 sq m of maintenance space spread over 12 mechanical, electrical and instrumentation shops: There is a central shop for all machinery, welding and fabrication. There is one shop for the 25 pieces of handing equipment installed under the modernization project; and seven area shops for electrical and mechanical work. These shops do some small fabrication, but are mainly for employee tools, information and documentation.
“We have all the prediction maintenance technologies: vibration analysis, lubrication sampling and analysis, and thermographics,” says Beaudry. “We do predictive maintenance based on condition monitoring — for example, monitoring the speed of equipment so that if it runs out of spec, an alarm goes off. We look at equipment parameters. We do maintenance when equipment falls out of spec, but is still functioning. This is a way to reduce maintenance.”
The core maintenance is done in-house, Beaudry notes, but the HVAC, some balancing and some motor repairs and hydraulic cylinder work are contracted out. A specialist contractor, Bussire & Frchette, a GE division based in Montreal, sends a crew in for work such as circuit breaker calibration. Another specialist contractor, the Corporation d’entretien prdictif, performs lubrication analysis.
Cisco, Hewlett Packard, Siemens and other firms have fixed contracts to maintain or repair control equipment, such as that used to run the automated carrier.
The peak maintenance shifts are 6:30 a.m. to 2:30 p.m. or 7:00 a.m. to 3:00 p.m., and they are coordinated with the production shifts. Maintenance people are on site around the clock, seven days a week. “There are always two electricians and three mechanics on site, all the time, plus people with pagers on call, plus one supervisor available,” says Belanger.
The biggest challenge to the maintenance department since the company horses were put out to pasture — CCR began operations in 1931 — has been during the four-year modernization project and the two years since the new equipment was booted up. “The whole project was one big maintenance challenge,” Belanger says.
The existing production equipment had to be maintained while the new equipment was lowered in through the roofs. At the same time, many of the maintenance personnel were unavailable because they were involved with the new equipment installations.
Belanger explains: “The maintenance people were all motivated to learn how to work on the new equipment. We had to do two things: One, we had to increase the level of training of our electricians. We had to make them into electronics technicians and increase their knowledge on network operations with 30 programmable logic controllers (PLCs) and 120 frequency controllers that are found in the automated equipment.
“Two, how do we train our people in the application of the new equipment? On the electrical and mechanical side, we designated four craftsmen in each area as trainers. They went to the manufacturers like Fermont [the carrier manufacturer works directly for Union Miniere Engineering of Belgium, which did the concept work for the new systems] and to Aisco in Burlington, Ont. [a division of Outokumpu of Finland]. They received training there and participated in the factory acceptance tests and the site acceptance tests.
“You name it, they were there in all steps,” says Belanger, from the construction of the equipment to the site acceptance tests and beyond. “The craftsmen also work as instructors to teach the hourly workers on the floor. There was some pairing and on-the-job instruction.”
Although the MEC (cathode stripping machine) is thirteenth-generation equipment and already had maintenance documentation, Belanger says that all the rest of the equipment is first generation. “They integrated a lot of concepts to come up with the new equipment.”
“Some reliability information was available for some of the components,” says Beaudry, but the maintenance team is continuing to optimize the maintenance schedule and techniques.
Cooperation between the equipment operators and maintenance staff has been unusually close, says Belanger. “The relationship between maintenance and the operators is to be applauded. We have to have close rela
tions between them. They were working together as a team. At startup, there were problems, and they worked together to find out what was wrong and why. The operators now understand more of what it takes to maintain equipment.”
The maintenance crews have done their share of head scratching as they learn to troubleshoot the equipment. “A tough example,” relates Beaudry, “was when a bay carrier was stopping in its track and we couldn’t figure out why. It turned out that the wheels had worn down less than 1/1000 of an inch, causing the sensors to misread the distance the carrier had travelled [thus stopping it too soon]. It took us a while to figure out why.”
Quiet and clean, yet harsh environment
The copper refinery is surprisingly quiet and the air in the facility is cleaner than one might expect. Yet, says Beaudry, “because of vibration, it is a harsh environment for the precision equipment, of which there is a lot.” There also are corrosive chemicals to deal with.
Take, for example, those cameras mounted on the automated carriers, say Beaudry and Belanger. The cameras position the carriers over the cells by looking for black dots on rectangles of plastic located by the cells. The positioning tolerance is a demanding plus or minus 2 mm. The maintenance people do regular predictive maintenance to see if each piece of equipment is within tolerance. The cameras are checked for tolerance limits once a month, and the camera systems are overhauled every three months.
Says Beaudry, “The challenge is controlling big precision equipment in a corrosive environment.”
Montreal-based Carroll McCormick is a regular contributor to Machinery & Equipment MRO.
Noranda uses Six Sigma methods to help optimize operations at CCR. Says Yves Beaudry, CCR’s reliability superintendent, we have improved “condition monitoring using statistical tools; data collection concerning the equipment condition, failures … this has helped to increase reliability.” Noranda has sought to understand the main effect of equipment breakage and link this with equipment availability, he adds.
CCR announced that it would launch a reliability program in January 2002. “The biggest impact will be on maintenance,” explains Claude Belanger, CCR’s superintendent of electrical and instrumentation maintenance. “The goal is to increase the availability of the plant and reduce maintenance costs by putting into place better maintenance, better parts [management] and processes, and operator involvement.”
The assessment phase was completed in the spring of 2002. Beaudry explains: “We assessed the way we manage and define roles and responsibilities … and benchmarked them against other world-class companies. We want to increase plant capacity and the efficiency of all the plant operations. There are nine criteria on which the refinery was measured, including predictive maintenance, responsive maintenance and training.”
The implementation phase, to be completed in early 2003, will include planning and scheduling of maintenance. The maturation and audit phase will take an additional two years, says Beaudry. “Now that you’ve implemented new ways of doing business, what can you do to improve this? Companies are looking for a two- to five-per cent increase in overall plant capacity. This may be in the form of an increase in the quality, [production] rate or availability of equipment.”