A smart drill rig is doing its part for academia on a mountain side overlooking one of Scandinavia’s most prestigious educational precincts.
Gothenburg is Sweden’s second largest city with a population of more than one million residents in the metropolitan area. The city is located on Sweden’s west coast, with a picturesque archipelago, and it teems with its iconic trams. You will also find 30,000 planted trees, 810km of bicycle lanes and a fish market hall in the shape of a church.
Furthermore, Gothenburg is a centre for research with about 3000 researchers, teachers and doctoral students at the University of Gothenburg. Here, world-class research is being conducted.
The university offers some 1400 courses and 190 programmes, making it one of the most popular universities in Sweden.
Two of the university’s eight faculties – the Sahlgrenska Academy and the Faculty of Science – are located at Medicinareberget (Medical Student’s Mountain, where education and research in health, medicine and dental care is conducted. The facilities are now being expanded with a new building for future research by the Faculty of Science.
Since the work site is located on a mountain in central Gothenburg, there are several challenges and strict requirements for rock excavation.
Skanska, the project’s prime contractor, selected Stens Bergborrning AB as the sub-contractor for the drill and blast operations of the project.
“There are four key factors to make a project like this a success,” Skanska’s production manager Henrik Lindström said. “They are safety, noise reduction, dust management and vibration control. This was very important when we discussed what sub-contractors to bring on.
For the drilling operations, Stens Bergborrning AB checks all the boxes – largely thanks to their choice of drill rig.”
Oscillating crawler tracks
The drill rig in question is the SmartROC T35 from Epiroc. It is equipped with a noise reduction kit that lowers noise levels by about 10dB, which makes it possible to have a conversation next to the drill rig with little interruption.
For this particular project a central dust collector is employed, creating a closed system for dust management.
Apart from drilling for blasting, the rig will also be used for rock reinforcement and bolting. The hole diameter used for drilling in this application is 64-70mm and further into the project 45-52mm drill bits will be used.
There will be four benches in total, reaching 20m meters down. This means each bench will have a height of about five metres. Blasting times are strictly regulated and limited to two times per week – on Tuesdays and Thursdays at 12:30am.
Now, drilling in close proximity to existing buildings in an urban environment is always challenging.
Considering that these buildings are research facilities in full operation with extremely sensitive equipment makes the challenge even greater.
Add to that a rough and unprepared terrain and you have a perfect application for the SmartROC T35. A key feature that gives the drill rig its outstanding terrainability are the oscillating crawler tracks.
Another challenge is to co-ordinate operations such as overburden removal, drilling, blasting, hauling, and rock reinforcement. This means that planning and communication is essential.
“These drill rigs are the best on the market,” Victor Åkesson, a drill rig operator from Stens Bergborrning, said. “Especially when it comes to terrainability and stability. Hands down.
“I have seen people dropping their jaws. They don’t understand how this machine can climb terrain like this without tipping over. Excavator operators sometimes come up to me, saying that they would love to have oscillating crawler tracks as well.”
Åkesson started his rock drilling career at the age of 15. He would accompany his father and founder of Stens Bergborrning, Sten Åkesson, to different projects.
The younger Åkesson is now an integral part of the company.
“This drill rig has been running for about 1200 hours since we bought it and just keeps on going,” he said. “This mountain that we are standing on has to be removed by the summer next year [mid-2020] so we really need this kind of reliable equipment.”
It is estimated that about 100,000 cubic metres of rock will be excavated before their job is done.
That might not sound like much if you were operating in a quarry. In a challenging urban development project like this with blasting limited to two times per week, with adjacent research facilities and strict requirements, it is a huge amount.
Noise levels are measured continuously on-site and the SmartROC T35 is way below required limits. Noise mainly comes from other machinery.
When the project is finalised and the new university building is in place, researchers can look out the window on the top floor and maybe they will spot that famous church – the one that has sold fish since 1874.