Modern Mining: Featured News

Sandvik Mining and Rock Technology continues to set the pace in underground mining with the introduction of its rock-reinforcement cable bolter with automated one-hole drilling designed to dramatically improve safety and productivity.

The unique Sandvik DS221L will significantly improve safety in mines by removing operators from the danger zone and providing immediate and active reinforcement on hanging walls when cable bolts are installed. This means the rock is already secured when the cable bolt is attached and mining can safely continue underneath areas where the grouting – which protects the bolts from corrosion – cures and hardens.

Automated cable bolter launched by Sandvik

The Sandvik DS221L is capable of rapidly installing pre-tensioned cable bolts.

The automated operation of the rig means that no hands-on operator intervention is needed, leading to faster and more precise drilling, cable pushing and grouting – and a process that can be reliably repeated. Bolt lengths can also vary according to the strata of the rock and can range from 1,5 to 6 m.

Technical cooperation

The prototype machine – which was developed in close collaboration with Two Rivers platinum mine in Steelpoort – was developed to specifically address productivity challenges faced by modern mines in South Africa and reduce the risks in the cable-bolting process.

According to Sandvik Underground Drills Business Line Manager Saltiel Pule, the Sandvik DS221L is capable of rapidly installing pre-tensioned cable bolts. An onboard batching plant and grouting system ensures bolts can be quickly grouted and protected from the elements.

“These cable-bolting operations are tedious in low-profile mining, prone to accidents and slow,” he says. “Our system is pre-tensioned and ensures immediate permanent support.”

Easy operation

The cable-bolting process requires the rig to be brought to the mining face, where it can cover a face area of 12 m² with the required number of holes drilled at 90 deg angles. Once set, a single operator lines up the turret before automated, one-hole drilling begins.

With the hole completed, the rods are automatically uncoupled and the turret is indexed to position the cable pusher and the specially developed cable underneath the hole. Then the operator spins the nut to expand the shell on the top of the cable and grip the rock – and secure the bolt in place. An onboard batching plant takes care of the grouting and ensures the hole is properly sealed to allow the grout to set hard.

The mobile rig is mounted onto Sandvik’s current carrier, making it easily manoeuvrable and familiar to operators due to its common control. The drilling is based on the powerful drifter RD314 (14 kW) already used on most D_211L-V machines, leading to simplified and reliable operation and the commonality of parts throughout an entire operation.

Maximum availability

In line with modern underground mine requirements, the Sandvik DS221L is engineered for safety with a variety of features that ensure reliable, efficient and precise bolting, and reduce the risk of unsteady or hazardous ground. It is compliant with current South African and European mining requirements and meets the specifications proposed by a knowledgeable team of geotechnical, engineering and mining professionals – as well as miners. It ticks every box in terms of productivity, safety and user friendliness, says Sandvik.

It is also built to be robust and durable with a compact turret that ensures smooth operation in low-seam areas. In digitalised environments, the rig is compatible with Sandvik’s OptiMine® monitoring system. As for suitability, the Sandvik DS221L cable-rock bolter has completed a gruelling 12-month trial at Two Rivers mine where it successfully drilled and installed over 1 000 m of cable holes of different lengths and diameters on a single-shift-per-day cycle.

“With a strong technical team from Two Rivers providing their input, and our own design and application teams providing constant input, this has been a tough and challenging project,” Pule says. “Now as we move toward completion and the final industrialisation of our bolter, it is rewarding to see its success knowing that this machine will save lives and offer higher productivity in our mines.

“Two decades after pioneering low-profile mining equipment in South Africa, the Sandvik DS221L is a new member in the low-profile family that will deliver safer, faster and more productive mining.”

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