Sandvik recently introduced another new drill rig for use in smaller-scale drill and blast method tunnelling operations, and also briefed T&T on its view of how trends are continuing to develop in a number of areas, such as the mass-scale introduction of large electric battery technologies still being far more in underground mining than in tunnels.
What is for tunnels, though not exclusively, is the company’s recently launched DD322i two-boom, compact drill rig which it sees as being advantageous for smaller-sized tunnel openings. It is also to be used in the underground mining sector.
A key trend continues to be towards more instrumented and intelligent tunnelling drills, Tommi Salo, Sandvik’s product manager for tunnelling drills, tells T&TI. Customers continue to seek more multipurpose equipment to support activities, such as injection drilling and pipe umbrella drilling, and also using hollow bar anchors in addition to traditional face drilling.
ADDING TO THE OFFERS
Previously, Sandvik introduced the DT923i jumbo rig to the tunnelling market and also the latest version of its iSURE excavation process control software.
The DT923i jumbo came with improved boom design and the SRH rod handling system, such as to support injection drilling in tunnelling projects like Stockholm metro with its relatively hard rock. Its introduction completed the i-series, following the earlier launch of the DT1132i. The jumbo has two electro-hydraulic booms with drilling functions computer-controlled automatically and uses RD5 series high frequency rock drills.
The group also offers the AT umbrella pipe system, through its subsidiary DSI Underground; the iSURE 8.1 version of its excavation process control information management software system with more advanced analysis of metrics to produce Key Performance Indicators (KPIs) from collected data onboard the i-series drill rigs.
Most recently though, in late 2022, Sandvik launched its DD322i two-boom drill rig for use in smaller excavations in both tunnelling and mining. It is compact enough with a new carrier and design, including a low profile cabin, to be able to tram in small headings, tight corners and intersections. The DD322i rig also has a Boom Control While Tramming (BCWT) option.
Field testing of the product took place almost a year ago in Finland before it was introduced to the market, in a global launch, later in 2022. Its predecessor was Sandvik’s DD321.
The DD322i was “very successful and well-received” by the field test customer, Jari Talasniemi, product manager for development drills said in a statement, adding that the BCWT option – which allows an operator to have improved, simultaneously control of two booms while tramming – proved useful for their mine development activities.
The system has new SB55i booms with two roll-overs to enable improved drilling performance (19.3m2 of side coverage, which is 48% more than the DD321) – and accuracy, and flexibility to drill crosscut and bolt holes.
The SB55i (TS2-520) instrumented boom – with has a 1.4m-long extension – enables precise, quick positioning of the drill feed, and hole angles can be visually represented on the cabin’s control screen.
Salo tells T&T that the DD322i can work on excavations of small tunnels ranging upwards from 3m x 3m (HxW) to 6.8m x 9.5m.
It also has scalable automation packages, including semi-automatic drill bit change, and also offers teleremote drilling control. This enables not only better drill utilisation, says the company in its statement, but continuous working hours over shift changes and during blasting and ventilation times. But in the cabin, which has been redesigned for a low profile, the new larger glass doors provide 55% more visibility. Displays are larger, too, for operators who can use the interface’s compatibility with the company’s digital systems – iSURE, as mentioned, as well as DrillConnect, AutoMine, OptiMine and My Sandvik.
In checking its service support needs on site, Salo tells T&T that the DD322i uses the same platform components as bigger jumbos.
Separately, last year Sandvik launched its new RS410 raise boring cutter, which has a new design, tougher carbides and – depending on rock conditions – up to 20% longer service life that helps reduced timeconsuming downtime for cutter changes. The aim is to eventually offer only the RS410.
For mines, primarily, Sandvik also recently launched a new addition to its Alpha thread range – the Alpha340 asymmetric drilling tools. It replaces the Alpha330 and, the company says, has up to 30% longer service life and also more productivity in face drilling (43mm – 51mm dia) and bolt operations, as uncoupling is easier, in both mines and tunnels. The thread concept also comes with improved drill bits.
The Alpha330 is to be phased out.
The main Alpha product used in tunnelling remains the Alpha360, Salo tells T&T. The Alpha360 was launched just over four years ago, in late 2018.
A further recent launch, again for mines but of interest in wider underground excavations, is Sandvik’s launch of a digital convergence system for ground support – xCell Cyclops. The senor system provides wireless, continuous, remote and real-time measurement of ground movements, while also featuring built-in notifications and alarms.
In announcing the launch, the company commented that underground mining is generally trending deeper, leading to more challenging ground conditions including squeezing ground and seismic events. The system can be fitted onto rockbolts already installed. It is a subscription service, the company adds.
ONGOING TRENDS
While new power technologies become more economical and move closer to adoption at scale, those such as large electric batteries are still making more headway underground in the mining sector. Sandvik has continued to add to its large supply contracts for battery electric vehicles (BEVs) to mine owners.
Salo points out, again, that tunnelling drills already provide a hybrid solution, in that drilling is electricpowered while tramming is enabled by the diesel engine – and is only needs to be done relatively briefly, compared to mining, as tramming distances are usually short.
He maintains his view, though, that given the trend toward BEVs that in about 10 years or so almost all new tunnelling drills will be such types of vehicles, he tell T&T. As noted before, key driver will be in how contractors look at the total cost of ownership (TCO) of BEVs against diesel equipment, for that comparison would change perspectives. In mining and tunnelling, he says, BEVs need less maintenance, and electric grids are in place underground allowing ongoing charging, as drilling is underway so saving time.
Another trend that continues is remote training, which was given impetus during the restrictions on travel and contact during the Covid pandemic. To that end, Sandvik has its Digital Driller package.
A BEV development drill for mining – but can be used in tunnelling, with boom changes – is the company’s DD422iE. While the DD322i has been added to the development drill family, being a more compact rig and focused on potential to excavate smaller tunnels, it has a low emissions diesel engine. However, it can be fitted with engines certified to more restrictive environmental standards.
