Located in the town of Pyhäjärvi in the south of Oulu province, in central Finland, the Pyhäsalmi mine is an underground copper and zinc mine, owned by Canadian mining corporation First Quantum Minerals.
With a depth measuring 1,444 metres, or 4,738 feet, it is the deepest metal mine in Europe and among the continents oldest. It origins date back to 1958, when a local farmer came across gossan ore during a well construction. A sample of this ore was soon delivered to Outokumpu Corporation, which, following analysis of the sample ordered a more thorough geological survey to be conducted on the area. Said survey revealed a rich volcanogenic massive sulphide (VMS) deposit rich in copper and zinc, and come 1959 the decision was taken to open up a new mine at the site of the ore discovery.
The Pyhäsalmi mine opened on 1 March 1962. For the first five years it existed as an open cast pit, before underground mining operations commenced in 1967. Outokumpu was responsible for designing an underground development plan for the mine and in 2001 completed the construction of a 1,450 metre deep automated hoisting shaft. A year later the mine was acquired by Inmet Mining, who continued forward with the underground development plan. Fast forward to 2013 and the company found itself being acquired by First Quantum Minerals as part of its purchase of the Inmet Mining group.
“Through the history of operations here more than 50 million tonnes of ore has been successfully mined,” states Managing Director, Kimmo Luukkonen. “Based on the most up to date information available we estimated that we have approximately five years of mine life ahead of us which will take our mining operations into 2019. During this time we anticipate an additional seven million tonnes of ore will be mined, taking the recovered ore from the deposit to around 60 million tonnes in total.”
Pyhäsalmi Mine Oy, a fully owned subsidiary of First Quantum Minerals, charged with operating the mine, today uses non-entry, bulk open-stope mining methods in a primary-secondary sequence. On average, stope size varies from 50,000 tonnes for narrow primary stopes to over 100,000 tonnes for wider secondary stopes. Meanwhile, milling at the mine involves crushing, three-stage grinding, conventional flotation using three separate circuits, and water removal to produce copper, zinc and pyrite concentrates.
“Looking back over the history of the mine one can clearly see that it is a development that has always prospered from the use of the latest technologies, and best practices and processes,” Luukkonen continues. “For its part, Outokumpu has always been recognised for employing cutting-edge technologies, many of which originated from its own in-house research and development division, which was a rare thing to have during the 1970s and 80s. What we have done since taking over operations at the mine is continue to utilise new techniques and tools to get the most from the mine, an approach which extends to every area of operation. For instance, years ago the mine employed what was the first Sandvik cable bolter. Today we continue to strengthen our partnership with suppliers and contractors like Sandvik in order to retain our leading position in areas such as automated production drilling and automated loading.”
During 2013, the mine was responsible for producing 14,900 tonnes of copper at an average grade of 1.1 percent, and 21,700 tonnes of zinc at an average grade of 1.9 percent. “Our figures for last year were very much in line with what we would consider normal for the mine,” Luukkonen says. “Annual tonnage figures have remained fairly stable for the better part of decade now, averaging some 1.4 million tonnes in total per year. Of course, when it comes down to it, you can only mine what you have in front of you, however our processes and methods of operating have always been strong and we feel this is reflected in our results.”
In the 52 years that the mine has been in operation it has been has a massive impact on the region in which it operates, an impact driven by the fact that when it comes to the town of Pyhäjärvi’s tax income alone, the mine is responsible for contributing one third through the payment of corporate taxes and other associated costs. Meanwhile, it is estimated that another third of the municipality’s tax income comes as a result of indirect effects of the mine. This of course poses a question as to how the municipality will adapt when operations at the Pyhäsalmi mine does come to an end.
Understandably, the end of the mine’s life is an event that the operators are well prepared for, perhaps all the more so as the mine faced a similar scenario in the mid-1990s when, faced with only a few years of operations remaining, a new ore body below one kilometre in depth was discovered.
“When it comes to the end of mining operations here, we have to consider the fact that what we have here is an extraordinary asset which is not only among the deepest mines in Europe, but also one of the only ones to possess access ramps that all vehicles can use to reach the very bottom of the shaft,” Luukkonen explains.
The unique size of the asset and its logistical strengths has already seen it earmarked as the potential base for a number of exciting future ventures. These include being a candidate for future pan-European particle physics research projects. Another potential future use of the mine could be to support pumped-storage hydroelectricity projects.
“While talk of what the future may hold for the mine site is interesting, it is equally as important to consider the future of our skilled, experienced and dedicated work force,” Luukkonen enthuses. “They are the individuals who have contributed most to the success of the mine and as such we are hard at work developing a retention plan. Although we have no doubt that there will be no shortage of opportunities offer to our employees once the mine ceases operations, we want to do all we can to recognise their contributions and retain their skills and knowledge.”
Turning back to today and the mine’s outlook for 2014 looks bright, what with production levels of copper, zinc and pyrite all looking to remain in line with previous years. “We are certainly on the right path when it comes to this year,” Luukkonen concludes. “Our job from here on out is utilise the time we have left here to get the most out of an incredible asset which has already delivered so much.”