Modern Mining February 2021

ROOF SUPPORT AND ROCK DRILLING

Roof support and rock drilling: the safety

In terms of safety, roof support is arguably the backbone of every underground operation. In this feature, Modern Mining takes a look at this complex area of underground drilling, as well as at the

trends, technologies, product offerings and their uptake in the underground mining industry. By Mark Botha .

T he US Nat ional Inst i tute for Occupational Safety and Health (NIOSH) estimates that rock falls at underground mines cause some 30% of fatalities and around 15% of all injuries that occur in these mines each year. In the words of Saltiel Pule, business line manager (Underground Drills) at

Sandvik Mining and Rock Solutions, “the importance of roof support cannot be overstated. It is a complex area of underground drilling which forms the back- bone of safety at every underground mine.” Roof support trends He says current industry trends are characterised by large opencast mines moving from surface to under- ground operations and by gold and platinum mines becoming deeper. “Operations are being extended into brown- fields,” he says. “The deeper the minerals are, the more complex roof support becomes as you deal with faulted and complex hanging wall ore-bodies in the reef horizon. “Rock is not homogenous. It is constantly under stress and driving tunnels through it destabilises it. There is therefore a greater focus on safety and,

Saltiel Pule, business line manager (Underground Drills) at Sandvik Mining and Rock Solutions.

because of the increasing depth of these mines, on secure production.” He says that, as a result, customers are now look- ing for efficient and effective roof support strategies and optimised excavations. “Another trend is to move away from manual roof support installation where some 10 000 roof bolts can be installed per annum, to mechanised instal- lation whereby up to 25 000 bolts can be installed per year.” Deeper mines are also moving away from con- ventional, dynamic roof bolts to seismic-enabled dynamic bolts designed to withstand seismicity, and automated bolt technology with pumpable resin and grout for increased safety and speed. In addition, miners are looking at smaller-diame- ter holes and self-drilling roof bolts. Automation and digitalisation Key drivers for digitalisation and automation in roof support are increased safety, reduced exposure of people to unsupported areas, efficiency in the min- ing cycle and, importantly, data and analytics to enable smart mining. “We need to analyse where and how to install the support. For this, we need data on factors such as machine pressure, water flow to the machine and the cost-effectiveness of the rock tools. We also need data on instantaneous penetration rate; the amount

Sandvik digital driller training simulator develops and refreshes operators’ skills on the Sandvik i-series drill rigs.

22  MODERN MINING  February 2021