Heritage Cases

In the recent past, Sterkfontein Caves have undergone intermittent instability; the latest being a rock fall on the 5th of January 2014. Besides forcing a closure for a period of time, the incident prompted concerned authorities to formulate remedial strategies for the preservation of the caves. The caves, being a complex natural structure, are faced with many surface and sub-surface triggering factors, i.e. geotechnical, hydrological, environmental and seismic factors. The challenge of ensuring stability of the caves can be achieved by applying Digital Mine Concepts. For the enhanced safety and stability of the caves, a two-pronged approach which integrates Real-time Ground Behaviour Monitoring and Numerical Predictive Modelling for the authorities to take precautionary and stabilizing measures respectively has been proposed. The monitoring data will be gathered continuously through remotely communicating digital sensors with threshold limits specified for stresses, strains and vibrations. The numerical modelling covering both back analyses and validation of the observed behaviour will be used to evaluate geomechnaical parameters, idealize constitutive behaviours and perform simulations to predict/forecast stop specific behaviour. Having idealized the requisite parameters and constitutive behaviour, findings of the numerical modelling will then be used in the GIS-based ground behaviour monitoring model to economize on the time and effort. An initial permit (permit ID:2560), which is attached with this new application, had been issued for the period between 04/08/2017 and 31/08/2018. It took a while to conclude the agreements between Wits University, Maropeng and the company with experience on the installation of safe technology systems (Ramjack Technology Systems). Considering the importance of this installation for both the Caves and the Wits Mining Institute (WMI), we are now asking for a new permit to be issued for a duration of 3 years. The purpose is the same, i.e. for the installation of ground behavior monitoring sensors and researching a safety system at Sterkfontein Caves. Also attached, is a document called 'Project Charter for the implementation of the Mine Hop, Conspec, MDT, uGPS systems. Wits University Sterkfontein Caves – South Africa 01st October 2018'. It gives a description, scope of work and plans for the installation of the sensors at the Caves. Images for the identified sites for the sensors are also included in the document alongside dimensions of the sensors and where applicable, details on depths for drilling works. The installation of the system require drilling of holes to first, install brackets and second, to support loose blocks of ground.