Thursday, 27 June 2019: Technical Visit

Technical Visit - Mponeng Gold Mine
  AngloGold Ashanti’s Mponeng gold mine, located south-west of Johannesburg in South Africa, is currently the deepest mine in the world. The operating depth at Mponeng mine ranged from between 2.4km to more than 3.9km below the surface by the end of 2012. Ongoing expansions have resulted in deeper digging at Mponeng, pushing the record to beyond the four kilometre mark.

Thursday, 27 June 2019: Site Visit

Site Visit - University of Pretoria Geotechnical centrifuge facility

About the Facility

Physical model studies are a versatile means to investigate a wide range of engineering problems. A geotechnical centrifuge is used to accelerate small-scale models to high accelerations to impose a stress distribution within the model corresponding to that occurring in the full-scale situation. For example, a model with a scale of 1:50 needs to be accelerated to 50 times the earth’s gravity to impose the same stresses in the model as in the field. This is necessary in instances where realistic material behaviour depends on the correct stress distribution. Typical applications include geotechnical and mining related problems.

The Department of Civil Engineering at the University of Pretoria operate a 150 G-ton geotechnical centrifuge at their Hatfield Campus. The centrifuge was produced by the French manufacturer Actidyn. The centrifuge is capable of accelerating a model weighing up to 1 ton, to 150 times earth’s gravity. The centrifuge model platform measures 1,0 m x 0,8 m with unobstructed headroom of 1,3 m. The radius, measured from the centrifuge axis to the model platform, is 3 m. The centrifuge offers a range of user configurable electric, pneumatic and hydraulic services to monitor models and drive a wide range of actuators required to model engineering processes. A total of six cameras, including a facility for high speed photography, are available. Centrifuge tests can be managed and observed remotely via an internet link.

The centrifuge is currently used to model aspects of cave mining in collaboration with the Australian Centre for Geomechanics. Another study involves the modelling of cavity propagation to the ground surface to study factors affecting sinkhole development. A collaborative project with the Universities of Cambridge and Durham in the UK are also underway to study the performance of wind turbine foundation on expansive unsaturated soils.

See the full conference programme here...