It has been 30 years since Pekka Nieminen joined Finland’s Tamrock in 1987 as an application engineer in the surface drilling business. “I was making calculations about the equipment that Tamrock would supply. It was a global role based in Finland. But soon after I moved to France to cover south western Europe,” he says.
Supporting European distributors meant travelling between markets such as France, Spain, Portugal, Northern Africa, Belgium, and the UK. Three years later Nieminen headed back to Finland. But as a global company his role remained very international and in 1997 the firm went on to be acquired by Swedish Engineering company Sandvik. “Sandvik do encourage moving around within the company. I was based in Finland but looking at underground product lines for Asia Pacific. I had to get up early as they wake up earlier than Europe,” he notes. “I was also travelling a lot up until 1997. Then I was involved with major projects.”
This change of focus saw Nieminen working on equipment requirements for major hydropower or tunnelling projects. “We worked hard to package offerings for the customers including drills, loaders, and crushers from different suppliers,” he says.
Nieminen remembers one such project as a particular career highlight. The challenging Sedrun tunnel, was perhaps the most complex part of the epic 57km Gotthard Base Tunnel through the Swiss Alps. “We worked on that from early 2000 to early 2007. We were the equipment supplier for the excavation of that project. It was very challenging rock, it was deep below the mountain, maybe 2,000m below the surface and it was very fractured rock, which had high compression so they had to excavate the tunnel larger than it needed to be and let it compress and get smaller,” he explains.
Working for the Transco-Sedrun consortium of Swiss contractor Implenia, Germany’s Frutiger, Bilfinger Berger and Italy’s Pizzarotti, the scheme was both logistically and technically complex. “There was a lot of bolting and rock support and special equipment to do the drilling. To reach the worksite there was a 1km horizontal tunnel and then shafts constructed. All the equipment needed to be dismantled before it could be reassembled [at the face] to start work.”
The diameter of the face was 12m but excavation was sometimes over 13m to account for the squeezing. Initially the contract involved construction of tunnel 2km in either direction out from the access shaft using drill and blast with drilling jumbos for face profile drilling including the Axera T11-drilling jumbo. “Today’s type would be the DT1231 range,” says Nieminen. “There were also special machines made for that project only,” he says such as the AxeraT12-Sedrun with drilling booms and two extra heavy duty utility booms and capability for umbrella drilling.
“The contractor seemed to be happy with the equipment and we had a distributor Avesco in Switzerland who took good care of the machines. He had a permanent set up on site to service the equipment,” he says.
As the drill and blast went on construction of subsequent tunnel sections was being carried out using a tunnel boring machine. “There were TBMs approaching from both sides but the drill and blast was faster than anticipated so the drill and blast was extended, an extra 1km for all four tunnels,” notes Nieminen.
ROCK SOLID
Being involved in the world’s longest tunnelling project was not something that Nieminen had originally envisaged when he started studying mining and rock excavation at the University of Technology. “I was always interested in technology and mechanics but I didn’t know about mining before I went to university. It came up only in the second year,” he says.
Today Nieminen is vice president of the tunnelling drills business following the restructure of the company in 2016 which saw Sandvik’s separate mining and construction businesses merged to form Sandvik Mining and Rock Technology. “There are benefits as there was such a big difference in size. Mining was so much bigger than construction. I was in the construction business area heading the product area for breaking, surface drilling and tunnelling. Joining the combined business area, I am now in the business line for tunnelling drills. It is a smaller range of product and a smaller business but this is close to my heart and my history and it is my interest area as well.”
He described his job as a product management role. “The demand comes from the product line into us and in engineering and supply. We are telling them what we want them to supply. We are collecting the information from the market.”
Despite his passion for drills Nieminen says that his favourite product is the computerised drilling jumbos that first emerged in the late 1980s and have steadily grown in popularity. He learned most about these during his time supporting projects in South Korea. “It was a very positive learning curve in South Korea to see how good a job you can do on a jumbo with a good company. The things with computerised jumbos is that you can control the drilling, where to drill and you can drill accurately,” he says.
Today these sophisticated machines are now prevalent in mature markets. “In developed countries, they are the dominant machines for hard rock drill and blast. In many other countries, the management see the benefits of computerised drilling but it is not used in the operations so you don’t get the result.”
Sandvik’s computerised drilling jumbos use the iSure software first launched in 2008. The software has four main modules starting with iSure Tunnel which sets out the drill and blast design, drilling pattern, longhole pattern, tunnel line and all of the project files. Contrary to the traditional approach, the pattern is designed in the end of the round where successful blasting is at its most critical. This provides hole burden calculus and optimisation of hole location, thus ensuring optimised blasting and supplying better pull-out, decreased need for scaling, increased rock loadability and smoother collaring in the following round. “The software to develop the drilling pattern for the computerised jumbo gets the maximum capabilities out of the machine. When you design a drilling pattern right then you can get blasting results good and then you can get optimum results,” says Nieminen. “It is a very unique programme with unique features.”
The other three modules are iSure Report for drilling management, iSure Analysis package for taking measurements during drilling for rock analysis, and iSure Bolting which enables hole placement and direction, tools for hole generation and fan management.
MARKET MOVEMENT
This increased amount of data and development of software such as iSure is one of the biggest changes that Nieminen has witnessed during his career. “Understanding of accurate tunnelling has improved a lot. We had computerised jumbos when I joined the company in 1987, but there were very few customers seeing the benefit. The possibilities of the internet and networks, having a connection between the office and the site. That is something that we couldn’t do in the past.”
But the biggest challenge, says Nieminen, has been managing the market fluctuations that have inevitably brought peaks and troughs in demand over the past three decades. “It goes up and it goes down and to cope with that is the biggest challenge. Not just when it goes down but also when it goes up in terms of maximising all the opportunities. It is about resources around the globe, suppliers souring the resources, it is a big topic,” he says noting that mining countries invest in infrastructure when raw material prices are strong. GDP growth too is a major factor in demand.
In terms of technology Nieminen has witnessed the growth of mechanised tunnelling but it has not taken off as much as he initially expected it to. “When I was studying it was said that TBMs would grow fast and drill and blast would go down but I haven’t seen that in rock tunnels. They have grown fast yes but mostly in soft ground or earth or in the soil. For rock tunnels drill and blast is still most used and in hard rock and of course if the space is different [not circular] then drill and blast is the only option.”
Finland is of course home to some of the world’s most competent rock with ancient hard granites solidified under millennia of glacial ebb and flow. “It is said that 10,000 years ago there was 3km of ice that was on top of Finland and that pressure made the ice behave like a liquid so it was moving against the ground. It cleaned out all the sedimentary soft rock so there was only hard rock left with very low overburden and that is why the rock is good. It also smoothed out all the mountains,” explains Nieminen. Of course, with 30 years in the underground sector Nieminen has seen his fair share of poor quality ground. “I have seen tunnels in rock with almost no tension strength. Then you don’t need drill and blast, just drilling machines and excavator and a lot of support, concrete lining, steel arches,” he says.
Looking ahead Nieminen is happy in his role as vice president of tunnelling drills and has no specific plans to change. “It has been very challenging and interesting to be in this company. There are a lot of opportunities and a lot of changes.”
