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International collaboration
Chairholder: Prof Francois Malan
The support of Harmony Gold for the Harmony Gold Chair in Rock Engineering and Numerical Modelling continued in 2020. The Chair conducts research into techniques to simulate the rock mass behaviour in South African deep level gold mines.
A key objective when designing layouts for deep gold mines is to minimise “excessive” stress concentrations. This is currently achieved by elastic numerical modelling of the layouts and using historic design criteria such as average pillar stress and energy release rate. These two criteria are imperfect as they do not consider the extensive stressrelated fracturing of the rock mass that is ubiquitous in the deep gold mines. Other forms of inelastic behaviour, such as total closure, cannot adequately be considered when using these criteria. As many of the older mines exploit remnants, the question should be asked to what extent these criteria are valid in older mines and remnant areas, and if they are not, what alternative method should be used to estimate the stress distribution and associated hazard. A very important component of the planned work is the development of enhanced design criteria and appropriate numerical tools that can be used to assist with the layout design of these deep gold mines.
The following publications emanated from the work conducted in this Research Chair:
• Jooste, Y & Malan, DF. 2020. The need for improved layout design criteria for deep tabular stopes. Journal of the South
African Institute of Mining and Metallurgy, 120(1): 23–32. • Couto, PM & Malan, DF. 2020. Production rates versus seismic response in deep-level mining (accepted for the proposed International Society for Rock Mechanics (ISRM) International Symposium, Eurock 2020 – Hard Rock Engineering, which was to be held in Trondheim, Norway, in October 2020 (but cancelled due to the COVID-19 pandemic)
The following progress reports were also published during the period under review:
• Automated determination of remnant and crush pillar extraction sequence (20 February 2020) • Test of a proposed numerical model for pillar edge spalling (18 May 2020) • Effect of interface slip and pillar modulus on pillar loading stress distribution (18 July 2020) • Use of stored kernel tables for the efficient solution of tabular mining problems (24 August 2020) • Total closure and back-area stress (9 October 2020)
Prof Francois Malan and Prof John Napier play a key role in the research conducted in this Research Chair. The financial assistance of Harmony Gold contributes to the outputs of one PhD candidate (Yolande Jooste), and two full-time master’s students (Danél Wessels and Mesuli Mahlangu).
Chairholder: Prof William Spiteri
The AEL Chair for Innovative Rock-breaking Technology was established in the Department of Mining Engineering in 2018. Its purpose was to channel AEL Intelligent Blasting support into new technologies that would synergistically benefit AEL, as well as the Department of Mining Engineering’s research capabilities. This was also the first time that the Department had partnered with another engineering department at the University (the Department of Electrical, Electronic and Computer Engineering).
In addition to enhancing the AEL brand within the University, the Chair allowed AEL to exploit the Department’s virtual reality (VR) and augmented reality (AR) expertise and facilities to further strengthen AEL’s market and technology leadership position. These visual technologies can be applied advantageously in several areas, such as the training of AEL’s personnel and other stakeholders, and the 3D scanning of mining environments that would allow analysis and visualisation in an immersive, virtual setting.
During the period under review, the Chair supported ground-breaking projects that would resolve pressing issues within the mining industry. It focused on three projects, in particular:
• The development of a quantitative measuring technique to physically capture and study the in-flight motion of flyrock so as to improve on predictive models and better understand the causative factors • The application of VR technology to enhance the learning process of AEL’s personnel and related stakeholders. The assembly and operation of the Detnet electronic detonator system and components was selected as an initial pilot project. The gamebased programmes would allow problem scenarios to be interactively solved and the trainees’ performance evaluated. • The development of techniques to convert visual data (such as video footage obtained by a drone flying over an open-pit mine) into 3D VR and AR images. This work is being carried out by the Department of Electrical, Electronic and Computer Engineering under the auspices of the Chair.
