The implementation of solutions to enable the continuous breaking of rock from tabular, hard-rock orebodies should result in rock fragmentation that is easily loaded, transported and processed. The system must also maximise extraction by reducing waste mining, the need for pillars and achieve the industry goal of zero harm.
Research and development
Fire setting is the oldest method of non-mechanical rock breaking. Anglogold Ashanti invited Maxem, a construction company, to test the method underground. Promising results on the C-Reef resulted in full-scale trials being initiated.
Thermal spalling has been successfully implemented in deep-level gold mines, but its performance in platinum-bearing reefs has yet to be determined. Challenges identified during previous trials will be addressed, including the development of a system to efficiently clean holes, the development of automated control systems for operation and rock engineering, mine layout and systems design for various mining scenarios. The goal of the following year of research is to deploy and implement a thermal spalling mining system underground.
Findings
The research team developed a testing methodology for determining the spallability of rock samples and found that the best option is to apply a transient heat source to the circumference of the sample by moving it across the flame. A rig has been designed by MaXem to achieve this, and a regulator/torch is now required to control the flame. The design and manufacture of a thermal spalling prototype test rig are underway. The research team is considering the use of the artificial stope at the Mandela Mining Precinct.
Status
Ongoing activities under this project include simulation software training and the development of monitoring methodology for underground trials. Research on rock breaking mechanisms and proxy testing for spallability will also be undertaken.
