Sandvik’s DD422i. The i-series are Sandvik’s latest range of bolters. (Photo: Sandvik)
Reinforcing the Rock Mass
We look at advances in ground support components and their installation
with six key suppliers
By Carly Leonida, European Editor
Peter Bray, Global Product Manager for Rock Reinforcement Equipment at Epiroc, spoke to E&MJ about this. “There has been a noticeable increase in demand for dedicated bolting equipment over the past decade,” he said. “This is partially driven by the higher volumes of bolts required underground, but it’s also driven by an industry that’s placing a greater emphasis on safety. These dual factors have had a marked effect on the design and functionality of mechanized bolting equipment.”
Peter Young, Product Manager for Bolting, at Sandvik Mining and Rock Solutions’ Ground Support Division, added: “Deeper mines mean higher rock stress levels, greater seismicity, different rock mass qualities and environmental factors, such as warmer working conditions. Greater reinforcement is required, as well as dynamic ground support and advanced monitoring. These factors all impact rock support and equipment design, requiring different bolt types, mesh installation for the walls, roof and face, increased equipment automation and remote operations, and data collection from the complete bolt installation process.” High-stress conditions often lead to broken, fractured rock masses. Installation of bolts in these types of ground can be challenging, leading to longer installation times and questionable quality of the installation. As such, rock bolting is a common bottleneck for underground hard-rock mining operations. Balancing productivity and installation quality is a challenge that equipment and consumable suppliers are currently working to solve.
Another major challenge is capital investment. For most mines, ground support systems represent a substantial investment which must be balanced against the life of the system and its individual components, and the overall safety requirements throughout the life of the operation and/or stage of mining. Renier Koekemoer, Senior Product Manager for Hard Rock Drills at Komatsu, explained: “Due to the cyclical nature of mining where production is dependent on a mining method that’s as continuous as possible, the end goal for suppliers and miners is to install the right ground support system for their application as quickly as possible. This system needs to meet all their requirements which, first and foremost, include ensuring the safe, day-to-day operation of their mine by employees and equipment.”
These factors, alongside a drive for continuous improvement, have helped the industry develop a range of specialized and targeted ground support systems. “It has also stimulated the growth and sharing of ground-support knowledge on an international scale,” said Koekemoer. “We’re seeing broader collaboration from suppliers and miners worldwide to ensure the right ground support system is selected for each application — a selection sometimes based on what works in other segments with similar constraints.”
Rising to the Challenges
A significant portion of the above challenges
come from the costs associated
with mining practices. As mines get
deeper, traditional mining methods are
challenged and many operations now
lean heavily on innovative technologies
to speed the development and reinforcement
process.
Paul Stephenson, CEO of DSI Canada’s
Ground Support Division, explained:
“One example of this is the
move towards battery-electric vehicles
and the integration of bolting into automated
equipment — this is all about the
removal of people from the underground
environment and also to speed the development
of orebodies for recovery.”
Operational challenges combined with inflationary pressures mean that reinforcement practices have had to become more efficient to keep pace. The move towards the mechanization of smaller mining sections has been a key trend. Mechanization can speed up cycle times for ground support installation, but more importantly, it removes the operator from the hazardous space directly below the bolter and places them in a safe operator compartment. Continuous development towards semi and fully-autonomous ground support installations also maintains this.
Today, many mines use ground support systems that have been tailored to their specific requirements and some of these are pushing the envelope for both production and safety. They achieve this through greatly reducing the time that operators are exposed to hazardous conditions and through diversity of ground support, using the latest technologies to meet their individual requirements which could change on a day-by-day or even drift-by drift basis.
“With mining conditions becoming more challenging, there is a need for more mine-specific ground support products,” said Derek Hird, CEO of DSI Australia’s Ground Support Division. “It’s no longer about one product for all applications. Rock reinforcement needs to be adapted to the mine’s conditions to achieve the desired performance.”
Given the increased depth of mines and their susceptibility to both natural and induced seismicity, many recent design improvements for bolts have focused on dynamic performance. Others provide additional value through increased load capacity which lessens the requirement for support. A simplistic installation process also speeds up development rates, and there has been a greater focus on single-pass bolting technology in harsh environments in recent years. Sustainability is another growing trend, with some manufacturers looking to incorporate recycled packaging materials, while others are looking to longer term items, like green steel. Let’s look at some of the latest solutions available on the market…
Epiroc’s Auto-Bolt Reload
Gains Traction
Epiroc has been collaborating with key
industry partners in recent years to
develop a bolting system that utilizes
Self Drilling Anchors (SDA) and pumpable
resins. SDA bolts are not as sensitive
to variable ground conditions as
some other bolt types and offer consistently
fast installation regardless of
the rock conditions.
Bray said that, since its launch in September 2022, Epiroc’s new Boltec rig with Auto-Bolt Reload (ABR) functionality has seen strong market interest. The main design feature of the Boltec ABR is the fully mechanized bolt reloading system. This means that the system automatically feeds bolts from a large carrier magazine to the feed magazine while the operator remains safe inside the cabin. This innovation removes the need for manually reloading the feed magazine, thereby protecting the operator from potential trip hazards or falls of ground.
“This is a huge step forward in improving operator safety,” Bray told E&MJ. “Epiroc is in discussions with several customers who are interested in taking up the new functionalities and capabilities that the ABR system provides. The next steps in the development of the ABR system are in line with autonomous functionalities and these will be a significant step forward on the rock reinforcement automation journey.” He added that Epiroc is soon to deliver a prototype Boltec E10 S ABR machine to a customer for a field test. This will explore autonomous functionalities that will reduce the need for operators to be physically onboard the bolting machine.
“Automation, information sharing, smart bolts, and guidance systems are just some of the industry trends and technologies that are being worked into our development plans for rock reinforcement equipment,” said Bray. “It’s a very dynamic environment at the moment, which keeps Epiroc’s R&D department busy. There is never a dull day when working with bolting equipment!”
Komatsu’s ZB21 Goes from
Strength to Strength
Komatsu has been engaged in ground
support in a variety of ways for a long
time, including in both hard rock and
coal/industrial minerals applications.
The company’s latest product for
ground support is the ZB21 bolter which
was launched, along with the ZJ21 jumbo
drill, in November 2020. The ZB21
is designed specifically for bolting in
hard-rock mines with restrictive tunnel
sizes. It delivers long-lasting and continuous
ground support installations in
challenging conditions.
Koekemoer explained: “The ZB21 can achieve this largely due to the innovative design that allows the bolter to be extremely flexible and versatile while maintaining the high degree of reliability and ruggedness required from a hydraulically operated, mechanized bolter. One of its features is a patented screen handling system that is part of the bolting head itself, thus eliminating the need for additional booms or damage-prone attachments. These features, coupled with an agnostic approach to matching the Komatsu ZB21 with a variety of both ground support and drilling consumables, further extends the flexibility of this machine.”
This development will be available through the Komatsu drilling solutions group to allow for the conversion of nearly any host unit, further extending the ZB21’s application across almost the entire market. “The ZB21 continues to go from strength to strength as we see it being adopted in various markets ranging from Canada to remote and distant applications in Southern America,” said Koekemoer. “This will continue to expand, as the ZB21 also meets the requirements of mines in Africa and beyond. Although the machine launched with some unique challenges, the feedback and acceptance has been fantastic and definitely lays the foundation for the continuous development of this and other products designed to meet customers’ needs and requirements.”
Normet: Creating Perfect
Product Pairings
Rock bolts and cables are just two
components of a larger system used
to secure the rock mass which also
encompasses grout. These three elements
are inseparable. Normet has
seen great success over the years with
its D-bolt, but Martin Petranek, Director
for Products and Production in Rock
Reinforcement, said the company has
much more to offer.
“In rock reinforcement, Normet is
known as the D-bolt, supplier and many
customers were putting us in a ‘one
dynamic bolt specialty class’ supplier
box,” he said. “While Normet still mostly
specializes in rock reinforcement for
challenging environments, we have
much more to offer.
“Our R&D activities are heavily influenced by high-performance equipment for underground mining,” said Petranek. “Productivity is continuously increasing, and we need our productivity — in other words safety — to be ahead of them otherwise operations have to slow down. Other major influences come from Mother Nature; underground mines are getting deeper with faster developments. Our rock reinforcement systems provide a means for re-directing rock forces to help stabilize the rock mass instead of it doing damage. This is a never-ending battle and it brings the joy of challenge to this business.”
Sandvik and DSI Join Forces
The integration of DSI Underground
into Sandvik Mining and Rock Solutions’
Ground Support division in 2021
positions the company as a leading
provider of equipment and consumables
for underground hard-rock mining
and tunneling.
Peter Young, Product Manager for Bolting in Sandvik Mining and Rock Solutions’ Ground Support Division, explained: “Customers benefit from the additional value and expertise of these equipment and consumables suppliers working together to better understand their requirements. The Sandvik and DSI offerings are available separately or as a combined package, allowing customers to customize their fleet to support their operational needs.” The i-series are Sandvik’s latest bolters. The range includes the DS412i, DS412iE, DS422i and DS512i models. The i platform offers various levels of automation for rock support drilling. The high level of data collection during bolting allows operators to tell how well drifts and tunnels are supported with the possibility to document this information. The i-series also allows for offgrid drilling and bolting, and Sandvik’s patented Charging While Drilling technology means the DS412iE doesn’t need to draw from mine power network. It also offers a reduced charging time of less than 30 minutes per cycle.
The retrofittable design of the sensors makes them easy to install directly onto existing rock bolts. They are battery-powered and operate with highly accurate laser measurements, and can be connected via both Wi-fiand Bluetooth, providing operators with real-time access to data, built-in notifi- cations and alarms. This setup reduces the need for manual work and inspections in the mine, reducing costs and improving safety.
The xCell Cyclops system is available as a subscription service with three levels: Basic, Silver and Gold depending on the number of users at a site and devices in remote mode. Young said that interest in the system is so strong that a second intrinsically safe version for soft rock and coal mines is already under development. In terms of rock bolts, Sandvik and DSI have been working to expand their range of solutions for hard-rock mining. The companies’ most important dynamic anchors include: the POSIMIX Resin Bolt, Combination Bolt, the OneStep Bolt (a patent DSI bought from Hilti), KINLOC and the KINLOC Indie Bolt, the Inflatable OMEGA-BOLT and the MD / MDX Bolt which was originally developed by Sandvik Australia and has now been integrated into DSI’s product portfolio.
At the bauma 2022 exhibition in Munich last October, DSI showcased two dynamic bolts. The KINLOC Indie is a premium point anchored friction bolt which offers high-capacity performance to 250 kN. Point anchoring is independent of the friction bolt body providing stable anchoring during ground movement and shock loads. The Mechanical Dynamic Extra — or MDX — bolt was also on display. This offers extra expansion and anchoring capabilities thanks to a unique wedge design that allows it to expand by up to 60mm. While the MDX provides good support in squeezing ground, the way in which the shell, the wedges and the rebar interact also makes it perfect for use in seismic ground conditions.
In addition, DSI and Sandvik are expanding their range of injection chemicals, for instance, for use with DSI’s Mineral Bolt. DSI recently expanded its production capacity for injection resins and foams to over 20,000 t/y, and the production of FASLOC resin capsules to over 60,000,000 per year. These are produced locally in Brazil, Canada, Poland, South Africa, and Australia using a just-in-time supply system for greater efficiency.
SSAB: Quality, Safety
and Sustainability
SSAB’s inflatable rock bolt provides
instant support and a quick installation
process. Sara Valentin Eklöw, Site Manager
and Sales Director at the Virsbo
mill where the inflatable rock bolts are
produced, spoke to E&MJ about this.
“The main challenge for rock reinforcement
remains finding the best
possible product given the prerequisites
of the rock, especially as mines
go deeper and rock movements increase,”
she said. “At the same time,
bolting is a time consuming activity and
needs to be kept at a high pace, which
is why we believe inflatable bolts fit
well into solving many miners rock reinforcement
challenges. They meet the
requirements for safety and productivity
as well as sustainability, using only
high-pressure water to be installed.”
“Developing products that increase the speed of installation with higher corrosion resistance have been key development activities during the past decade, but there are still improvements to be made in terms of more efficient products. I also believe that lots of product development can still be made within rock reinforcement around softer parameters, such as environmental impact and quality. SSAB is leading the development of fossil-free steel, which will bring sustainable solutions to the mining industry in the coming years. Sustainability trends are yet to come into rock reinforcement, but the impact could be significant.”