Using qualitative risk assessment as a leading indicator for geotechnical risk in mining

Abstract

Investor confidence is largely driven by a mining company's ability to deliver on the guaranteed return on investment. Thus, robust due diligence processes, functioning as part of a mining company's corporate governance, become essential tools to identify hazards that can impact production, assess the associated risks and introduce controls to manage the risks. The geotechnical practitioner is tasked to manage one of the biggest risks on the mine; that of a rock mass instability. Since an instability, or collapse, need not be large to have a significant impact on production, the challenge is to develop an optimised life-of-mine design with a risk management plan that suits the risk requirements of the mining company and investors, whilst meeting acceptable, minimum safety standards. The concept of a Geotechnical Review Board has been adopted in the industry as a vehicle to provide assurance that the geotechnical risks on a mine have been identified and are being properly managed. The review relies on external parties providing appraisals of the design and processes, and experienced oversight of the active operations. In general, these reviews tend to have a unique style; often a combination of the current, visible, critical issues on the mine and issues deemed as important by either the reviewer or a third party. Coupled with the challenge of fluidity in modern planning environments, the geotechnical practitioner is often still faced with uncertainty in the level of geotechnical risk associated with any given mine plan. This paper introduces a geotechnical risk assessment tool that has been developed for use as a leading indicator within AngloGold Ashanti's international operations. The authors aim to provide the reader with insight into how the tool can be utilised to understand a mine's ability to proactively identify and manage geotechnical hazards, by exploring the following components: Introduction to a questionnaire, which is the main input, and serves as a means for the practitioner to assess the geotechnical engineering activities being conducted on the mine compared to best-practice in the industry. Using a qualitative geotechnical risk matrix to report the status of the primary hazard control classes and the overall geotechnical risk on the mine compared to others in the company. Establishing a reliability index for the geotechnical engineering system (GES) on a mine, which can be used to illustrate how the mine's GES compares to that of a project (ranging from conceptual to feasibility level), design and construction phase, operational phase, and industry best-practice.

An integrated geological characterization of the Mid‐Pleistocene to Holocene geology of the Sørlige Nordsjø II offshore wind site, southern North Sea

“…In geotechnical hazard and risk assessment, the risk is defined as the likelihood of harm occurring from a specific hazard (e.g. Hamman 2009). We therefore summarized our preliminary geotechnical risk assessment for SNII by creating a colour‐coded map showing areas associated with particular geohazards and their likelihood of causing harm (in this case, installation challenges for offshore wind turbine foundations).…”

Understanding, managing and communicating geomechanical mining risk

“…Finally, they provide input to the company risk policy/strategy. From a risk perspective, it is important to have the appropriate type and level of geomechanical technical expertise for the complexity of the site/project (Hamman and Venter 2019). The requirements for a seismically active deep and high-stress underground mine are quite different than for open-pit slopes.…”

“…Geomechanical data should be shareable, transportable and secure and continuously kept up to date (Hadjigeorgiou 2012). For example, Hamman and Venter (2019) reports that the implemented data process flow at AngloGold Ashanti's international operations includes well-defined procedures that include: collection of data, securing of data, reporting of data, validation, data packaging. …”