Technical innovation reduces vibration injuries

When the YouTube video starts, all you see at first is the man, the hi-vis clothing and the huge drill. Only when looking more closely do you notice the rapids in the background and the fact that the man in the video is in a harness and suspended in front of the rock face 180 metres above the turbulent water. He works with rock face stabilisation, and the video shows him embedding large bolts into the rock face to prevent rockslides. 

“Norway has countless roads and railways running close to mountainsides, and to ensure that they’re not affected by rockslides, we need to stabilise the rock faces,” explains Thomas Clemm, a physiotherapist and head of corporate healthcare at the Norwegian company Mesta AS. 

Vibrations from drills can cause severe neurological damage 

Rock face stabilisation is actually an entire industry employing some 2,000 people in Norway alone. And while efforts to prevent rockslides and thereby protect both lives and infrastructure are important, they present a major problem: the drills used by rock face stabilisation workers vibrate, which can cause severe neurological damage. 

“When I surveyed our employees a few years ago, we found that they had extremely high exposure to vibrations, and that many of them had problems with, for example, fingertip sensitivity,” says Clemm. 

Vibration injuries – such as vascular injuries, numbness or the loss of fine motor skills in the fingers – are often chronic and comprise the most common occupational injury among men in Sweden today. However, when Mesta AS discovered the extent, they decided to try to do something about it. Clemm contacted the researcher Hans Lindell at RISE, who for many years has led projects aimed at reducing vibrations in the work environment in partnerships between RISE and a large number of companies and organisations affected by vibration injuries. The aim is to reduce vibrations in the work environment. 

“I’d met Hans before and knew that not only was he extremely knowledgeable about vibrations, but also had invented a technical solution that could lessen the vibrations. So, I got in touch and asked whether he and RISE would like to work with us,” Clemm explains. 

Developed vibration damping in both drill handles 

The result was the No Bad Vibes project (Ingen dårlige vibber in Norwegian), with Lindell and his colleagues developing vibration damping for both drill handles, which reduced vibrations to one sixth in one handle and to half in the other. 

“Since the level of injury grows quadratically, this means that the risk of injury, compared to before, is now only one thirty-sixth as high for one hand and a quarter for the other,” Lindell explains.  

But that was not enough. The project has also tested modifying the rock drills with ATVA, a technique that Lindell and his colleagues invented. 

“ATVA entails inserting a weight into the machine that is then connected to the machine via a spring. The laws of mechanics cause it to oscillate backwards and forwards, thereby creating an opposing force to the vibrations from the compressed air.” 

Since these forces are of equal size, they cancel each other out, reducing the vibrations by about eighty percent.  

“We’ve tested ATVA on other machines before and always with the same results, namely that we prove that you can greatly reduce both the vibrations and vibration injuries,” says Lindell. 

For Mesta AS, the damping handles mean that fewer employees will suffer vibration injuries, and Clemm now hopes that machine manufacturers will start incorporating ATVA in their products. 

“The technology that Hans Lindell has developed is a major step forward! He’s someone with many ideas who always sees opportunities, and we’re extremely pleased to have been able to work with him.” 

Beneficial even in the mining industry 

Moreover, people working with rock face stabilisation in Norway are not the only ones who would benefit if more manufacturers incorporated this new technology in their machines. 

“Consider the mining industry, and how many people around the world work with hand-held rock drills under poor working conditions. If machine manufacturers were to incorporate this technology as standard in their machines, it would improve the work environments of very many people. The cheese slicer is probably the only tool to have changed less than drills in the past seventy years, so we’re pleased to have finally been able to do something about it,” says Lindell.

Photos: Mesta AS

Rock face stabilisation in practice