Towards a safe mining environment: the development of a framework to model and manage the risk of flyrock

Abstract

Flyrock incidents at Anglo American Plc operations, as well as across the broader mining industry, have highlighted the significant safety risks associated with flyrock. These incidents pose a serious threat to personnel, while also causing potential damage to equipment and infrastructure. More than half of the observed flyrock exceedances are not reported nor investigated. The underlying issue is not a lack of blasting standards but rather a failure to systematically capture and address flyrock risks throughout the drill and blast process. To overcome these challenges, this research aimed to develop a framework for modelling, monitoring, measuring, and reporting the risks associated with flyrock occurrences to enhance risk management strategies. The study sought to determine whether the current models used for flyrock prediction are effective in identifying risks and explore techniques for monitoring flyrock occurrences. To answer the research questions and achieve the aim of the study, historic incident reports, blast videos, and drill and blast data from various Anglo American Plc operations were analysed. Furthermore, the flyrock monitoring strategies currently used at the mines were reviewed to identify shortfalls and areas of improvement through the establishment of guidelines. The study identified gaps in the drill and blast process to assess the risk of flyrock. As a result, the process was ammended so that the risk can be verified and validated at various stages. The prediction models utilised in commercial drill and blast software were reviewed. The study confirmed that the current predictive model in use at Anglo American Plc operations, sufficiently identified flyrock risk. A flyrock risk reporting dashboard was also developed and implemented as part of the study to proactively raise flyrock risk awareness for every blast. The occurrence of flyrock is not as a result of ‘pressing the button’ to initiate the blast, but in most cases it is the consequence of a decision or action taken earlier in the drill and blast process and the establishment of the framework will help address the lack of risk awareness of flyrock. Recommendations out of this study also include amendment of the drill and blast process flow to cater for flyrock prediction modelling at various stages in the process, ultimately using the latest blast hole charging status. It is also recommended for future work to extend this framework to include secondary blasting and cater for fragment rebound distances in the estimations and monitoring.