UNDERGROUND DRILLING
A Komatsu ZB21 bolter and ZJ21 jumbo drill were recently delivered to a gold mining operation in South Africa
already proving its value in the field, with a recent delivery of both units to a gold mining operation in South Africa.
The ZB21 bolter stands out for its ability to complete 100 % of the bolting cycle from the operator’ s compartment, including screen installation, significantly reducing manual interaction and improving safety. This fully-enclosed workflow is enabled by an integrated screen handler and chemical injection system designed to streamline installation and shorten cycle times.
Versatility is central to the ZB21 design. The machine can install multiple bolt types – mechanical, friction, chemical and hydro-expanding – with two major types handled from a single carousel, giving operations flexibility across varying ground conditions. It can be optioned with 5 ft( 1.5 m), 6 ft, 7 ft and 8 ft bolting heads, with configurations offering positional adjustment to accommodate multiple bolt lengths and expand application adaptability.
Despite its compact footprint at just 5 ft 6 in( 1.7 m) wide and under 10 ft( 2.9 m) high in tram position, the ZB21 delivers excellent tunnel coverage, Komatsu says, with a vertical reach of up to 6.4 m. Long-life Montabert drifter options( JZD08, JZD10,
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JZD12) enhance drilling productivity while reducing consumable costs.
“ The result is a durable, agile bolting platform engineered to maximise uptime and minimise cycle inefficiencies – critical in today’ s high-demand development environments,” Komatsu says.
Complementing the bolter, the ZJ21 jumbo drill offers usable face coverage of up to 66 sq. m, a notable benchmark for a small-class unit, Komatsu claims. Its innovative boom geometry enables efficient drilling of lifters and perimeter holes, while supporting operation across variable grades and heading sizes.
A defining feature is the commoncarrier platform shared with the ZB21, allowing mines to convert between bolting and drilling configurations with minimal retraining. This standardisation simplifies operator adoption through intuitive controls and reduces the learning curve across fleets, Komatsu says.
Engineered for uptime, the ZJ21 incorporates optimised service intervals, ground-level maintenance access and a front-end geometry that limits damage exposure, improving reliability in demanding conditions. Drifter options( JZD12 and
JZD21) manufactured by Montabert feature advanced energy recuperation and damping technologies to enhance performance while lowering total cost of ownership. Both drifters can be fitted to either fixed or telescopic feeds, providing flexibility to match application needs, the company added.
Komatsu concluded:“ The recent deployment of both the ZB21 bolter and ZJ21 jumbo drill at a South African gold mine underscores the practical benefits of Komatsu’ s modular platform strategy. By combining broad coverage, compact design and shared systems architecture, these machines enable mining operations to improve productivity, reduce training complexity and respond more effectively to evolving underground conditions.”
Battery-powered drilling
Sandvik Mining has just unveiled the new Sandvik DD423iE – the second machine in its next-generation battery-electric development drilling offering.
Following the launch of the DD423i diesel counterpart in March, Sandvik has now added a battery-electric option that, it says, combines proven drilling performance with significant advancements in productivity.
The new Sandvik DD423iE sets a new benchmark in underground battery-electric drilling, delivering a 50 % increase in battery capacity and tramming range compared with the DD422iE, alongside an 80 % improvement in battery drilling performance. Tramming speed has also been enhanced by 30 %, making it the fastest machine in Sandvik’ s underground drilling portfolio, the OEM says.
The DD423iE can deliver more than triple the charging power while drilling, enabling a full 0-100 % state of charge in approximately two hours – less time than required to complete a full drilling round – significantly improving operational efficiency.
In addition to these electrification advances, the Sandvik DD423iE retains the performance improvements of its diesel counterpart. These include 34.5 % greater drilling coverage, 48 % improved cross-cut performance and the integration of new SB75i booms with double roll-overs.
Operator safety and productivity are further enhanced through a 55 % increase in visibility, while maintaining more than 95 % machine availability in demanding mining conditions, Sandvik claims. New lightweight covers make serviceability easier with improved accessibility to main components.
Field testing at Agnico Eagle Finland’ s Kittilä mine validated these performance improvements in real mining conditions, according to Sandvik.
A representative from Agnico Eagle Finland noted the superiority of the DD423iE’ s performance versus its
International Mining | JULY 2026