Modern Mining February 2021

ROOF SUPPORT AND ROCK DRILLING

Sandvik Intelligent Control Architecture (SICA) is a control platform which provides comprehen- sive diagnostics on the system, including machine pressures and rock penetration rate. Roof support technology When asked about emerging technology in the roof support field, Pule refers to Sandvik’s high- and low- profile cable bolters. “The Sandvik DS221L low-profile cable bolter installs pre-cut cables from 1,5 m to 6 m in length with expansion shell, nut, plate and post-grouting, and has been on testing and trail since 2018, with positive customer feedback by the four major plati- num producers in South Africa and Zimbabwe.” He describes the bolter as a “one-person operated rock reinforcement drill rig specialised in mechanised and cement-grouted cable bolt installation.” The bolting operation is performed by an opera- tor located at a safe distance from the dangerous work area. Once the space below the cable is made safe through cable pre-tensioning, the operator attaches a hose for post-grouting, by hand. “People have died, not while installing the sup- ports, but while trying to make the roof safe,” says Pule. “So, we rather make the roof safe by means of a remotely controlled machine.” The DS221L LP cable bolter is currently in its commercialisation stage. When it comes to high-profile bolters, Sandvik Mining and Rock Solutions has the largest fleet of Cable bolters in the massive mines within its regions, says Pule. “We recently delivered two Sandvik DS421 rock reinforcement drill rigs to a large South African dia- mond mine. These rigs are specialised for cement grouted cable bolt installation in underground mines and tunnels.” The DS421 can install cable bolts up to 25 m in length, with several steel strands per hole. It features an on-board cement mixer, cement bag platform and steel strand reel for continuous cable fit. “It is therefore autonomous for more than a shift.” Key offerings “Our key offering in terms of bolts are boom and turret mechanisms which provide accuracy, hole alignment and the ability to handle very challenging bolt applications. Sandvik Mining and Rock Solutions offering can install most bolt types at different holes sizes, with maximum bolt capacity.” The Sandvik RD314 high-frequency hydraulic rock drill is at the heart of this offering as it drills fast and improves the roof support cycle time. The company has also recently upgraded its Sandvik DS211 low- profile bolter, as well as the DS311 rock support drill and the DS411 drill rig. Pule says the company has been “at the fore- front” of rock reinforcement, with products for both

The company’s local office is expected to take delivery of the new Sandvik DS412i, a highly auto- mated rotary blasthole drill for underground mining, destined for a local diamond mine. “This is an intelligent machine,” says Pule. “The operator sets it up according to the rock engineer’s requirements and provides it with a bolting pattern from the geotechnical engineer. Upon completion of the task, the machine analyses the drilling and reports any deviations.” Face rigging is performed autonomously. With the DS221L low-profile cable bolter, the bolt- ing operation is performed by a single operator located outside of the dangerous area. Once the area underneath the cable is safe thanks to the cable pre tensioning, the operator attaches the hose for post-grouting by hand. It features an Automatic Resin Injection (ARI) system whereby the amount of resin needed is pre-programmed for every hole. The machine ensures that the resin will be installed in the holes according to the rock engineer’s requirements.

Bolting mechanisation ensures the integrity of bolt installation.

24  MODERN MINING  February 2021