Advancing and applying smart technology is improving miners’ ability to delineate geological structures more accurately, which is important because a key aspect that affects safety in the sector is the variability of rock mass characteristics over time and space, says consulting engineers and scientists SRK Consulting.
“Our understanding of variability can be improved by collecting more data and improving the quality of this data. Tech- nologies, such as photogrammetry, provide us with Big Data capability, and can also feed into a more effective, risk-based design approach,” says SRK Consulting chairperson and principal mining geotechnical engineer William Joughin.
He further explains that the developments in mobile mapping enable SRK to survey underground tunnels, for instance, and monitor deformation over time. “Using older technology would take weeks to achieve what we can now do in just a day – providing us with more information to design more effective support solutions.”
SRK Consulting is working with a number of partners including the Australian Centre for Geomechanics (ACG), based at the University of Western Australia, in Perth, which is developing a program called mXRap.
Joughin says SRK is collaborating with ACG to develop apps within the mXRap program, which aim to manage seismic hazards that are particularly dangerous for deep-level mines, adding that a range of applications is being developed to analyse seismic information to improve the safety levels in deep mines.
One of the main aims in mining is to remove workers from risky areas close to the working face. This has been done successfully in many underground mines, but is more difficult in deep-level South African mines, owing to the shallow dipping, narrow-reef mining environment, he explains.
“Nevertheless, efforts to automate mining methods in these narrow stopes continue, which often requires a change in mining layout and rock engineering strategies.”
Joughin says South Africa has been the focus of SRK Consulting’s deep-level mining work for the past four decades, as the country is home to most of the world’s deepest mines. “While the rest of the world refers to anything more than 1 000 m below the surface as a deep mine, in South Africa we refer to a mine as being deep level only when it exceeds about 2 000 m. A mine that is more than 3 000 m deep is then called ultra-deep level. Only Canada has mines that approach the depth of ours.”
He tells Mining Weekly that the company has provided rock engineering expertise for deep mines worldwide, and is currently working with an underground mine, in the Democratic Republic of Congo, on a feasibility study to deepen operations to about 1 600 m below surface.
SRK’s contribution to these projects relates mainly to designing mining layouts and mine support systems, as well as conducting reviews, due diligence studies and accident investigations. “We are also often asked for our opinion with regard to challenging and high-risk aspects of the mine planning process, such as the extraction of shaft pillars and remnants,” he adds.
Joughin explains that to mine successfully at deep levels, practical solutions are developed and applied to keep excavations stable under the enormous pressures associated with mining at depth, pointing out that “these solutions need to carefully balance risk and cost while prioritising the safety of personnel”.
He adds that the solutions must also protect the mine’s infrastructure, such as shafts; therefore, the design must ensure sufficient distance from stress concentrations and hazardous geological structures.
“The application of modern technology can help us to implement practical solutions, but it is no easy task to introduce sensitive digital instruments into the underground working environment.” Moisture, heat, dust and confined spaces can affect the introduction of high-technology equipment, with such demanding operating conditions underground requiring this new equipment to be robust to operate effec- tively over long periods.
“But this is all part of the evolution process that we must all continue to pursue in the interests of safer and more productive mining at depth,” Joughin concludes.