Building the future of rock reinforcement at Kemi Mine

Deep beneath Finland’s northern landscape, Outokumpu’s Kemi mine is pushing the boundaries of underground mining. As the country’s only chromite mine and a key part of Outokumpu’s fully integrated stainless-steel production chain, Kemi mine plays a vital role in supplying sustainably produced ferrochrome to both local and global markets. With mining progressing toward deeper, more demanding conditions, the need for robust, adaptive ground support solutions has never been greater.

As underground operations at Kemi mine have progressed, changes in stress profiles in the rock mass have created fracture zones between older surface operations and the underground working areas. These fractures have allowed water to infiltrate certain zones, creating significant challenges for the installation of traditional cement-grouted cable bolts.

 

“Cement-grouted bolts are not usable everywhere. Water washes the cement away, and for this reason we must develop”, explains Arto Palokangas, Mining Operations Engineer at Kemi mine. “We have acquired new equipment so we can use resin bolting to reinforce these fractured rock zones and water-bearing areas. It’s significantly faster and brings major cost efficiencies”, says Palokangas.

Depth brings further challenges beyond water infiltration. As the mine expands into even deeper orebodies, including a trial mining area at about the 900 level, the overall ground conditions become increasingly demanding.

 

“The rock types at Kemi mine, both ore and host rock, are very soft in terms of strength, which already creates challenging mining conditions,” says Marko Matinlassi, Senior Rock Mechanics Engineer at Kemi mine. “As stress increases, we need additional reinforcement methods. Self drilling bolting has become an extremely valuable tool.”

This is where Epiroc’s Boltec with pumpable resin technology and extension drilling with Self Drilling Anchors have delivered a breakthrough. Traditional cable bolting struggles in broken ground: when the drill string is pulled out, the hole often collapses. With SDA technology, the bolt is installed as it is drilled, eliminating the risk of hole closure. Pumpable resin is then injected through the bolt, ensuring complete encapsulation, even in areas of voids and fractured rock conditions.

 

“We can pretty much guarantee a high-quality installation every time. It’s faster, safer, and more sustainable because you don’t need to return for rework. In challenging ground, SDA bolting with resin completely changes what is possible”, highlights Peter Bray, Epiroc’s Global Product Manager for Rock Reinforcement.

For operators, the experience is equally positive. Arttu Ylitulkkila, Boltec operator at Kemi mine, says resin bolting has become a natural part of the workflow.

 

“In highly fractured rock, if the rock has begun to swell and expand, this method can stop that swelling. Resin bolting is significantly faster than other methods, especially in broken rock – and without cement dust.”

 

Beyond solving immediate technical challenges, SDA bolting and pumpable resin also pave the way for greater automation. “Teleremote bolting is already a reality,” Bray explains. “Auto-bolting is possible today, allowing mines to continue reinforcement during shift changes or breaks. And because the machine logs everything it does, the mine gains traceability and confidence in every bolt installed”. For Outokumpu, where safety and productivity are top priorities, this marks a significant step forward.

The result reflects what becomes possible when two organizations commit to solving hard problems together. For over two decades, Epiroc and Outokumpu have worked side by side to develop solutions that meet these evolving challenges.

 

“Our cooperation with Outokumpu started in the early 2000s,” says Kim Halonen, Key Account Manager at Epiroc. “Cabletec is largely the result of joint development with Outokumpu, and Boltec has followed the same path”. Outokumpu has been among the first to adopt several key technologies, from the earliest Rig Control System (RCS) controlled Boltec units to their more recent battery-electric bolting machines.

Outokumpu and Epiroc continue to advance toward shared goals: enhanced safety, higher productivity, and the long-term sustainability of mining operations. With ore reserves extending well beyond 2050, the innovations developed together will only become more critical.

 

“Kemi has always embraced high technology,” Bray adds. “From being early users of Cabletec and Boltec, to adopting automation and now SDA bolting with pumpable resin – they are true innovators.” 

 

As the ground becomes more challenging, Kemi mine’s reinforcement strategy is evolving with it – and with Boltec extension drilling and SDA bolting, Outokumpu is better equipped than ever to face the depths ahead.