The Raiseboring Revolution
Equipment and services for raiseboring are in high demand and R&D is booming
By Carly Leonida, European Editor
In a part of the mining sector that has stuck steadfastly to traditional equipment and techniques with some manufacturers resisting digitizing their rigs (for good reason, conditions in raiseboring are extremely demanding), these developments represent an important step toward increased speed and safety.
New(ish) Kid on the Block
The Rhino 100, which is often attributed to Sandvik, was in fact was developed by the team at TRB-Raise Borers. The two companies share the same Tamrock history and, when Sandvik took over Tamrock in 1992, it retained a minority share in TRB. “Ever since those days, Sandvik has been our distributor and relationship has continued to be very close. Sandvik makes the tools, we build the rigs,” CEO Jarko Salo said.
“We are a relatively small, but very flexible company offering different services to the mining industry when compared to standard players. We customize and want to offer unique solutions. And, this is where the Rhino 100’s origins are. We listen to our the customers very carefully, meaning, historically, we have not been ‘everybody’s supplier,’ but the situation has changed in a big way during the last couple of years without any formal marketing effort. The rig and the results have really done the marketing for us.”
TRB offers a range of Rhino raise boring products from small to large diameter raise drilling. The prototype Rhino 100 was launched 2012 at Outokumpu’s Kemi mine in Finland, before heading to neighbor, Agnico Eagle’s Kittilä mine 2014. “Kittilä and their mine design really took full advantage of the capabilities and we received tons of inquiries based on their results,” Salo said. “And, now the mining operation revolves around two Rhino 100s. They have really turned their operation around with this new method.”
The next few years were spent interviewing customers at mines around the world and, after incorporating these views into the latest Rhino 100 design, TRB launched Gen3 in early 2017. The rig has been further developed over the past 12 months with the addition of a Plug’n’Drill module — the current cause of excitement within the industry. This allows one rig to be used for both upward slot drilling and back reaming with changeover in 30 minutes.
“Plug’n’Drill was originally deemed a crazy idea, but our original Rhino 100 concept is versatile and sophisticated enough to allow it,” Salo said. “Certainly, there are other rigs, which can drill both directions, but customers were not that happy with them. Previously down-drilling rigs had difficulty handling the falling muck if drilling up … Similarly, up-drilling rigs had trouble drilling down because the rig was designed for something else. Gravity plays a role in drilling operations and how the output is handled. Some rigs can be turned around and equipped for the alternative drilling direction. However, the results were not optimal, and it required a lot of manpower, time and space… hardly a solution for production drilling.”
With Plug’n’Drill, a single operator can switch the drill direction quickly (while underground), with little effort and the drilling module is optimized for the job: up drilling, down drilling or conventional raiseboring. Salo said the rig offers at least three times the capacity of other rigs in its class and some customers have seen productivity gains of 30% or more.
“We call it world’s fastest raise borer,” he said. “One mine claims the Rhino 100 contributed $6 million to its bottom line in one year. The rig resulted in 5.5% better recovery at its gold mining operation.” There are a number of reasons why both drilling directions may be required at a project: first, flexibility in the mine design; it is sometimes beneficial to be able to drill slots both upward and downward, and occasionally mine designs are changed partway through an operation’s life. Slots provide void spaces in the stope into which blasted ore can expand to improve fragmentation.
“Also, sometimes slot raising is done only upward. In such a mine, they may require escapeways and these are typically drilled down,” Salo explained. The benefit of the Rhino 100 concept is that, instead of bringing multiple rigs/ contractors on site, one rig can perform all tasks with the addition of one extra drilling module. It is much cheaper than the alternative making it especially attractive for remote sites.
“Demand has been strong globally, but more so in Australia. The Rhino 100 has taken the mining market by storm,” said Salo proudly. “Australian mines have seen the benefits of the new concept in slot raising and insist on using it in their production drilling due to the benefits. Single rig, single operator can dramatically cut the turnaround time and bring stopes online faster than ever before. Profits have soared.”
General Manager Mark Hanigan recently posted a video of the Rhino 100 with the Plug’n’Drill module drilling a 36-m-long hole at Gold Field’s Invincible operation on Linkedin, which received more than 11,500 views in just one week.
“The hole was for an escapeway and was drilled to 1.06 m in diameter with the reamer head being pulled through at the collar,” he wrote in the post. “Our average advance rate for reaming of the hole was 1.3 m per hour and was completed in three shifts. This new technology is proving to be the way forward for small diameter slots and raiseboring on a truly mobile carrier.”
In a press release announcing the project, Hanigan cited speed, safety and labor savings as three reasons why his team favor the Rhino 100. While it takes a team of two people between two and three days to prepare a traditional raise borer for duty, a single operator can tram the Rhino into the mine and be drilling within a matter of minutes.
When operating traditional raise borers, the operator is generally stood in the open less than 5 m from the hole being drilled and must drill deep into the rock before erecting a muck chute. “With the Rhino 100, the muck chute opens and closes,” Hanigan said. “You open it up, push through the rod, and when you’re ready to start drilling, you can close the chute up. It covers the hole, stopping the dirt cuttings flying out and hitting the operator. The Rhino 100 also removes the exposure of the operator to the risk of flying debris as you’re 6-7 m away from the work area and operate from within a cab.”
LKAB Sweden has also recently commissioned a Rhino 100 at its Kiruna mine and is set to trial the new Rhino Remote control module once disruption caused by the COVID-19 virus has died down. According to Salo, this is one of the first commercially available teleremote raiseboring systems. It removes the operator from the production drift, improving safety significantly. The Rhino Smart control system, which also features on the Rhino 100, allows measuring-while-drilling data collection for detailed performance benchmarking, all of which should add up to optimized operation. “I expect they [LKAB] will break all raiseboring records and will regularly be drilling more than 500 m per month,” Salo said. “I believe this will be a significant milestone in raiseboring history.”
Every contractor interviewed for the article noted an increase in the depth of raises they are being asked to drill over the past few years. “Shallow, high-grade deposits are becoming scarcer each year, and the industry is responding,” said Johan Davel, general manager for Raiseboring at Redpath. “Mining operations are progressing deeper, increasing the demand for ventilation raises, rock passes, escapeways and a variety of vertical development.”
Redpath provides in-house manufacturing alongside contracting services for its raise drill fleet. The company’s full suite of drills, from the Redbore 30 to the Redbore 100, offer the ability to excavate raises up to 8 m in diameter with depths greater than 1,000 m. Redpath is also a key player in the boxhole/upream market, with numerous purpose-built machines operating in world-class mines, globally.
Davel noted that, at present, global demand for raiseboring services is high, so these projects are actively engaging the majority of Redpath’s fleet and workforce. “The challenge is in managing demand and asset allocation to be able to suit all our clients’ needs,” he said. “In addition, the global COVID-19 pandemic is certainly a risk to our business that was not predicted at the beginning of the year. Redpath, and also our clients, are not immune to the risk it poses to the economy and our industry specifically.”
Redpath has embraced digital technologies to create high-tech performance and safety features, especially over the past five years. The company has deployed a variety of digital monitoring and automation technologies globally, with usage for these technologies increasing rapidly each month. “Newly developed safety innovations including intelligent machine behavior, which is allowing raisebore operators to mitigate the impact of adverse in-hole conditions. Redpath has had semiautomatic and remote capability for more than 20 years, and these new advancements will only further this technology as we move forward. Technologically advanced sensor arrays, which relay and record the current status of the machine are an integrated component of the Redbore drills,” Davel said.
Redpath currently is readying itself for two major Canadian projects, both of which will result in records within North America: one project will feature two raises, both exceeding 1,000 m in length far exceeding the current record of 845 m set by Redpath in 2010 — while the second project consists of a single raise with record-setting excavation volume. “We are proud and excited to collaborate with our clients, and look forward to safely executing these projects,” Davel enthused.
South Africa-based, Master Drilling, is seeing similar demand. “The main requirement for raiseboring is still for ventilation,” Izak Bredenkamp, group business development manager at Master Drilling, told E&MJ. “As mines get deeper, the demand will increase for raisebored holes. Our key markets are deep-level underground mines. In the RSA context, this is mainly for gold and PGM mines.” Master Drilling now has 152 raiseboring machines in its quiver, ranging from small to XXL in size for hole diameters of 250 mm up to 8 m.
“In the last five years, we’ve reamed around 500,000 m over various diameters,” Bredenkamp said. “We are currently busy with a world-record hole of 1,420 m deep at 4.6-m diameter that has to be directionally drilled. We have completed more than 65% of the pilot hole for this project.” The company also has some new projects under way in West Africa, mainly Ghana, for AngloGold Ashanti and Newmont.
Technological innovation and development remain a key pillar of Master Drilling’s focus and a significant business differentiator. The company recently introduced a Remote Drilling feature for its rigs. The first unit was successfully commissioned 3 km underground at the world’s deepest mine: AngloGold Ashanti’s Mponeng. Remote drilling enables operation of an automated drill rig from a remote location and, at Mponeng, the rig was successfully operated from the contractor’s site office on the surface.
The Remote Drilling system is a proprietary “plug and play” control and display module that connects to the drill rig’s local control module through the mine’s underground and shaft communication network. Master Drilling said by removing all personnel from the underground environment, this self-driven mechanism has improved production time and confirms that autonomous drilling technology is at the core of safer mining operations. Having completed testing, the Remote Drilling module has since been rolled out to sites in Mexico and Peru as well.
Focus on Efficiency
“In our experience the most important thing in raiseboring is efficiency,” said Bruce Matheson, sales and marketing director, Terratec. “There is a tendency in the industry to go larger, but this leads to inefficiencies as larger raises needs larger machines, which are difficult to move around. We are trying to see how we can increase the size or length of the raise without increasing the physical footprint of the machines, such as with our TR2000+, which has increased capacity over the 2000 model without an increase in the footprint.”
Terratec offers a full range of products from box hole, through down-reaming machines to traditional raise borers. It also has a multipurpose machine known as the Universal Borer that can perform all of these duties and be quickly re-tasked underground. “The continued upswing in gold certainly has not hurt us,” Matheson said. “In late 2019, Terratec celebrated the completion of a 300-m deep, 4.1-m diameter, ventilation shaft at Continental Gold’s flagship Buriticá mine development project in Colombia.
“Not all raiseboring equipment is capable of working with such robustness in these conditions,” Terratec Regional Raise Boring Operations Manager John Alejos commented on announcing the milestone. “Without doubt, this changing terrain is almost impossible to drill at such depths and such diameters. Only a team as strong as this, with the technical support of our on-site staff, is able to carry out such a task successfully and not without difficulties.” The TR2000+ was custom manufactured at Terratec’s workshop in Tasmania, Australia. It can comfortably execute raises of up to 500 m at 2.4 m diameter and larger ones up to 4.1 m diameter (of shorter depths). It has a maximum pilot drilling torque of 42,000 Nm, a reaming torque of up to 209,000 Nm and breakout to 236,000 Nm. The maximum down thrust force is 665 kN with up thrust being 4,150 kN. The total installed power on the machine is 360 kW.
Terratec has erred on the side of caution when it comes to digitizing its rigs. As Matheson put it: “contractors need reliable rigs that can ‘take a lickin and keep on tickin,” so systems have been kept as simple as possible to allow quick repairs and easy sourcing of parts — features that are particularly appreciated at remote sites and in production drilling when time is of the essence. A good example of this durability comes from the UB1000-R16 Universal Box-Hole Borer. The unit was delivered to a mining contractor for use in the Western Australian Gold Fields in 2014. The unit was specifically developed to meet industry requests for a 1.06-m-diameter box hole boring machine that would meet all Australian mine safety standards, plus be low profile, and could also be quickly switched to operate as a conventional raise borer, capable of pulling up to 3-m-diameter holes.
The UB1000-R16 went into service in late 2014, working in a narrow-vein gold mine, and was used to produce box-holed stope slots and escape ways, along with some larger, conventionally raise bored, ventilation shafts. A number of improvements were made to the machine in 2015, and it went on to operate almost continuously for more than two years, with no major downtime or repair interventions. In late 2017, the machine was taken out of the mine for some derrick maintenance work, plus a gearbox rebuild. Even though the gear box was well past its recommended hours between services, it was found to be in excellent condition.
Recent discussions between Terratec personnel and mine managers where the rig is operating indicate a high degree of satisfaction with the machine’s capabilities. “They highlighted its ruggedness, reliability and especially its flexibility. They are particularly happy to have a single machine on site that can perform box holes and medium-sized conventional holes, rather than having to maintain and schedule two different machines,” Matheson added. “Also, the ability to switch from box-hole to conventional mode very quickly gives the mine managers more flexibility to change their sequencing of holes later in the production schedule.”
Safety is Paramount
Safety is paramount to any mining project, and this is an area in which Epiroc has been particularly focusing its efforts. “Safety is always high up on our customers’ agenda and is Epiroc’s number one priority,” said Marcus Eklind, global business line manager, mechanical rock excavation, with Epiroc’s Underground Division.
“Safety concerns both the operators, the service personnel but also relates to the application. The raise needs to be completed in a way that is safe for the people involved but also for the expensive equipment used to do the raise. This pushes us to develop equipment that is soft on the drill string and the tools, yet productive, equipment that is safe to service and that can be monitored so that problems can be detected before they become catastrophic.”
Epiroc’s range of equipment includes models for both conventional raiseboring, boxhole boring as well as down reaming and covers diameters from 0.5 m up to more than 6 m. “We also offer the complete range of drilling tools such as drill-string components, reamers and cutters; we are a onestop- shop serving raiseboring customers around the world,” Eklind added. Epiroc recently released a new generation of its popular 90 series Robbins 92R. This is designed for power, flexibility and safety.
“With Epiroc’s latest available technology added to our raiseboring machine, we have prepared the rig for autonomous and remote operation,” Eklind said. “This model is now suitable for raises over 1,000 m long and diameters over 6 m while having the best size to power ratio of all raiseboring machines. With regard to tools, there is a continuous development to reduce downtime by reducing the need for lowering reamers for cutter change. This also greatly increases operator safety, since cutter changes are typically the only time operators are exposed to the open raise. Tracking product performance is made easier by having RFID tags installed in pipes and cutters. There is also the possibility to further develop live monitoring of the rock engaging products if the users value this kind of feedback.”
Epiroc introduced its CAN-bus control system on the Robbins Raiseboring machines back in the early 2000s and it recently introduced the fifth generation (RCS 5) on its raiseboring machines. “This has been a revolution for operators with a number of auto- and semiautomatic functions making it possible to accurately control the machine and the operation, thus increasing productivity without jeopardizing accuracy,” Eklind explained. “In recent years, telematics solutions such as Epiroc’s telematics system Certiq allow customers to remotely track and monitor the equipment. Other equipment used for the establishment of a raiseboring site, such as surveying tools etc., has of course developed a lot and this also allows for more accurate and precise set up of our equipment.”
Epiroc’s Easer L mobile raiseboring machine is currently being tested at LKAB’s Konsuln mine as part of the Sustainable Underground Mining (SUM) project. “There are two major trends in raiseboring. Longer and larger with the need for greater accuracy, and relatively short, small diameter raises driven by the need for an opening hole for blasting in largescale mining methods. In the later one, mobility and setup time is key, and this is where the Easer raiseboring system shines,” Eklind explained.
Since conventional raiseboring machines stay around for many years, much of the development work done to meet these trends are on the rock engaging part of the raiseboring system. Epiroc has also been investigating ways to help smaller machines cater to the need for longer, larger raises. Eklind said to do this, there are just a few parameters to work with, as the amount of torque and thrust that can be transmitted from the machine down through the drill string is given.
“Reducing the number of cutters required to dress a reamer increases the available load per cutter leading to more efficient breaking of the rock, even if the raiseboring system lacks capacity,” he explained. “This is where the six-row Magnum cutter comes to the rescue. With its 1-1/2-in. (38 mm) spacing and ability to run single coverage, larger and longer raises are now less stressful for the mine designers and raiseboring operators.”