Mikael Burck was fast asleep when the heart attack happened. The good news was that it was not his heart that had stopped beating. Unfortunately, there was also some bad news.
Boliden’s Aitik Mine outside Gällivare is not just the biggest opencast copper mine in Sweden, it is also the world’s most productive. Extraction of copper, silver and gold delivered sales revenues of SEK 3.5 billion in 2014. Aitik employs 700 people or almost ten percent of the entire local population of Gällivare. It is the largest private employer in the municipality. Five years ago, King Carl Gustaf officially opened the new concentrate works. That investment – the largest ever by the Boliden Group – more than doubled enriched tonnage to 39 million tonnes. A breakdown in the long and super advanced pipe network between drilling and transport is simply unthinkable. The consequences could be devastating for both Boliden and Gällivare.
Just before five on the morning of 13 August 2015, the alarm went off. Kent Engman, who was sitting in the control room at Aitik noticed that the pressure in the pressure line had dropped. It was probably not that big a problem – especially as it had happened after an already scheduled service stop – but Engman still had to make the seven kilometer journey to the recycling station to restart the pumps.
“As he gets them going again, he spots a leak from one of the pipe connections in the water pipe system. Kent tries to contact the control room, but realizes it is too late. He races out of the pump station just before everything goes bang,” says Mikael Burck, the Boliden Aitik Department Manager for electricity.
The concentrate works has a closed water system through which water continuously circulates. The water is pumped from the recycling station by pumps powered by motors the size of caravans (weighing over seven tonnes) up to the concentrate works. The pumps are the heart of the entire process. If the heart stops, everything stops.
Looked like a swimming pool
The huge water pipes that run to the recycling station are several kilometers long and have a fall of over 100 meters. In other words, they contain plenty of water – and the leak from the pipe rapidly turned the recycling station into a swimming pool. It was an irony of fate: the water that is so vital for Boliden’s operations in Aitik was in the process of drowning the motors that normally pump it round.
Burck reached for his cell phone. He saw the images he had got by MMS and realized he wouldn’t even have time to make himself a cup of coffee that morning.
“My first thought was that they were going to be stopped for quite some time. Then it was a question of starting to ring round to people.
The question was how long would operations be at a standstill? Was it a matter of days or weeks? No one could say for sure.
One of the first measures Burck and his team took was to organize shipment of the back up motor that was parked at ABB in Luleå, 250 km south west of Gällivare. In the meantime before that would arrive, the management team at Boliden in Aitik summoned an emergency meeting. During a video conference call with Håkan Bihagen, project manager at ABB and Erik Bohman, Technical Manager Motor & Generators at ABB in Västerbotten, they tried to form a picture of the breakdown.
“There was panic in the air,” says Bohman. “What should we do? How long is it going to take, we have to get an estimate of this. Things looked absolutely disastrous for the works. The motors as such are not the biggest problem. But the consequences of all the motors being out of action at the same time affected the entire concentrate works. You then don’t get any production and don’t earn a penny.”
“So everyone all sat there nervously until finally I thought, we have to try to be a bit optimistic. ‘Four days’,” I said. But that was being ridiculously optimistic.
“There was also a worst case scenario where we were talking weeks,” interjects Håkan Bihagen.
“Effectively, we had no information on how it had happened,” says Bohman. “We didn’t even know if any of the motors were still in one piece or if the water had penetrated into them.”
Service engineers on site
But some luck was on their side. By chance, John Sandström and Roger Andersson, two service engineers from ABB, happened to be on site in Aitik when the breakdown occurred. As soon as the water was drained off, they were able to start work loading the motors for shipment down to Luleå and then install the back up motor. Even though the works could not be operated with just one motor, when it was started it would enable Boliden to gain access to the important fire prevention and rinsing water.
“John and Roger worked round the clock up there. They really ran up their working hours. By lunch time the affected motors had arrived at the ABB workshop in Luleå, where Bernt Lidström and his team started working at record speed. Forcing out all the water, removing the ends of the motors, washing them and then inserting them in ovens and vacuum boilers to dry. Drying a motor takes time.
However, the motors proved not to have failed. Their resistance values, on the other hand, werefar below the desired value.
They lay around 1 megaohm, but we usually never dispatch motors that are under 1 gigaohm, so you can just imagine.
The signs were ominous. Bohman recalled a motor that had gone through a comprehensive review that had taken ten days to fully restore. His best case calculations suddenly did not look quite so hopeful. So – with the agreement of Burck and the rest of the Boliden management team – Erik Bohman decided to take a calculated risk.
“We drove one of the motors back up to Gällivare. Roger and John got it going manually, in a very slow and controlled way. After an hour or so, it started to switch on a bit more. Everything was OK.”
72 hours later
On Sunday evening – just over 72 hours since the original alarm, and 48 hours ahead of Bohman’s most optimistic forecast – Boliden Aitik was back on full power.
Even so, it could have ended in catastrophe. The installation error in the pipe connections that had caused the breakdown remained latent and the leak could just as well have happened in mid winter. The water would then have frozen in the pipes. And had Boliden and ABB not had such a close partnership – not least geographically – it would have taken far longer.
“ABB can really flex their muscles when they want to,” says Burck. It is important that you have a partnership with companies that can roll their sleeves up when necessary. They have such a great deal of know-how.”
“It is important for Boliden to have expertise quickly available when something happens, this incident shows how important this is,” says Bohman. We always aim to be close at hand. “You generate more business and more satisfied customers that way.”
A strategy that got Boliden’s heart beating again.
Text: Peter Ottsjö Foto: Patrick Degerman; Maria Fäldt;