SAIMM Annual General Meeting

Presidential Address

Presidential Address:

Managing geotechnical uncertainty and risk in mining

The science of soil mechanics is 100 years old, while rock mechanics is 60 years old. Although methods of analysis and design have been developed and have evolved over time, these are still relatively young sciences. The rapid increase in computing power and new technologies have enabled more sophisticated modelling and monitoring. However, there are still many aspects of soil- and rock mechanics that are not well understood. Geotechnical failures, which have major consequences, still do occur. These consequences may include environmental damage, major production holdups associated with loss of revenue, and loss of life.

High-consequence events, which are rare, are more difficult to anticipate and to design for, because by their nature they involve extraordinary circumstances or conditions, often geological in nature. These risks are usually mitigated by conservative designs and monitoring. Detailed geotechnical investigations help us to understand the natural variability of rock masses and identify unusual or unexpected conditions. Investigating and researching major geotechnical failures is essential to enable these unusual circumstances to be anticipated.

In the past, severe unanticipated events may have been treated as natural events or ‘acts of God’. However, society now has much greater expectations and it is essential to have policies and procedures in place that enable appropriate management of these rare, high-consequence risks. A good example is the Global Industry Standard on Tailings Management (GISTM), which was introduced after the catastrophic dam collapse at Vale’s Corrego de Feijao mine in Brumadinho, Brazil.

The address will explain the concepts of uncertainty and variability, and how they should be addressed in geotechnical design. The challenges facing geotechnical engineers, mine owners, and managers will be discussed, referencing a number of real case studies.

William Joughin – Biography

William Joughin – Biography

William Joughin was born in Johannesburg in 1967. He attended school in Johannesburg, matriculating at Parktown Boys High in 1985. William then studied at the University of the Witwatersrand for a BSc Eng. (Mining), which he completed in in 1989.

After a year of national service in Kroonstad and Pretoria, William started working for Anglo American Gold Division as a mining graduate. The first three years were spent on Elandsrand (now Kusasalethu) and Western Deep Levels East (now Tau Tona). During this time, he started an MSc Eng degree in engineering management.

William then transferred to the rock engineering department, where he discovered his real passion. He was seconded to integrated Seismic Systems International (now the Institute of Mine Seismology) to learn about mine seismic networks and rockburst management. He worked as a mine seismologist and a rock engineer for the next five years, on President Steyn no. 4 shaft (now Bambanani), then on Vaal Reefs no. 8 shaft (now Great Noligwa), Libanon, and Kloof gold mines. During this time, he completed his MSc Eng and -a GDE in Rock Engineering, as well as the Chamber of Mines Rock Mechanics Certificate, Advanced Rock Engineering Certificate, and Mine Manager’s Certificate of Competency.

William decided to move from mining operations to consulting in 1998, joining SRK Consulting as a Senior Mining Engineer (Rock Engineering). During the first few years, he worked on consulting projects for several mines and research projects for SIMRAC and DeepMine. In 2002, William arranged a three-year secondment to South Deep Gold Mine, where he worked as a senior rock engineer to gain experience in drift-and-fill and longhole stoping mining methods.

Upon his return to consulting in 2005, he started to develop his own client base and lead research and consulting projects. In 2009, William was elected as a Partner and head of the mining geotechnical department for SRK SA. In 2016, he was elected as a director and then served as Chairman of SRK SA from 2018 to 2023. He is a director of SRK Global. William is fortunate to have had the opportunity to visit and provide consulting services for mines in 18 countries on six continents. He currently serves on rockburst management advisory boards for El Teniente, Chile and Kiruna, Sweden.

William has published over 50 articles on rock engineering and is the recipient of an SAIMM gold medal and the Alec Wilson Award (SANCOT) for outstanding papers. He has co-written two chapters on risk-based design in the book Ground Support in Underground Mines (Potvin and Hadjigeorgiou, 2020) produced by the Australian Centre for Geomechanics.

William is a Past President of the South African National Institute of Rock Engineering (SANIRE), and a Past Vice President for Africa of the International Society for Rock Mechanics (ISRM).

He joined the SAIMM as a student and has been a Council member since 2008. William has chaired three international rock engineering conferences and two schools as joint SAIMM and SANIRE events. He is a member of the Publications Committee and served as Treasurer since 2020.

William married Sharon, an accountant, in 1999 and they have two boys, Michael (22) and Brandon (20). Michael is studying animation and Brandon is studying film-making, both at the SAE Academy in Rosebank.