In previous years, diamond wire systems were trialled at a number of sites in gold mines. The main implementation issue was wire failure due to rockmass closure. Challenges encountered with cleaning systems, transport of rock blocks and coordination of work crews highlighted the need for a full system design. The production of large blocks presents a major challenge with current mining layouts and infrastructure; however, this feature potentially allows for the transport of undiluted ore with no transport losses, potentially improving mine-call factors.
Research and development
The research team is investigating what the optimal mine layout would be to enable diamond wire cutting as a mining method. The methodology comprises core sample testing which will give an indication of on-site performance, thereby indicating suitability to reefs. This suitability informs mine design and guides site selection. The suitability to reefs also enables a comparative study of mining methods that will further support mine design and result in a greenfield design of a mine layout.
The research team arrived at two possible mine layouts: The current mine layout at Anglo American; and a revised version suggested by the research team.
In regard to handling and transport solutions, pushing was determined to be less effective due to the rock being partially fragmented after cutting. This led the team to explore several options including cutting the block the using thermal spalling on the isolated rock; cutting the block and then using a demolition robot for secondary breaking; and cutting the block, then drilling holes, followed by breaking the rock using expansive cement.
Ongoing activities under this project include simulation software training and the development of monitoring methodology for underground trials.
This research was commissioned to the CSIR and University of Pretoria.