LOCATION: PALABORA COPPER MINE, SOUTH AFRICA
Palabora is South Africa’s only producer of refined copper and has developed and operates a large US$410 million underground block cave copper mine with a production capacity of 30,000 tonnes of ore per day.
The Job / The Challenge
For years Palabora Copper Mine has been confronted with convergence in its current production level, with numerous contractors and products having been trialled in the past in an effort to reduce the convergence rate between the pillars and haulages. The rehabilitation phase sometimes takes up to one month to complete and needs to be repeated every four months, resulting in lost production time.
A recent issue that arose in the current production level (Lift I) was a new decline collapsing while being developed into a geotechnical structure without the essential support design.
The Solution
Normet proposed injecting TamPur 116 to stabilize the pillars because of its high adhesive-to-rock properties, flexural strength and the energy it can absorb when blasting activities occur in the same area. Its flexural strength allows it to move with the pillars.
It was agreed with the client that Normet would inject the first few pillars in the presence of the local contractor responsible for the rehabilitation. During this process, Normet trained the contractor’s personnel to do the work themselves in the future.
The actual pillars were 12 metres square x 4 metres high with 4 metre wide draw points between pillars and 4 metre wide haulages. The whole support pattern and structure are quite complicated, and this Success Story concentrates on the TamPur 116 application as it forms part of the support structure. 2,000 to 4,000 litres of TamPur 116 were injected into each pillar through self-drilling anchors of 6 and 12 metres in length. Normally, the client will rehabilitate three to five pillars at a time. The result reduced periodical rehabilitation in some cross-cuts from once every four months to once a year, with massive savings to the mine.
On the Lift II project, a decline had collapsed and Normet were asked to analyze the situation and propose a suitable approach. At that time there was a cavity, , above the hanging wall, up to 10 metres across, with loose gravel from the footwall up to about 3 metres into the cavity holding the face area marginally stable. Normet proposed a solution using self-drilling anchors with TamPur 116 and TamPur 125 because of their rapid reaction enabling the cut off of large water leaks, as water was running out of the cavity and face area. Due to the large volume of product required to fix the problem and the urgency, the client instructed Normet to airfreight all the product to South Africa to make sure a constant supply was available. A total of 42,000 litres of TamPur 125 and 112,000 litres of TamPur 116 was brought in and injected in 18 weeks. Finally, after TamPur 116 had been injected into the area, both declines were developed through the structure with no injury or rockfall.
When the declines were developed further down and turned back to the ore body, they approached the same geotechnical structure. This time, injection through self-drilling anchors started 10 metres in advance of the structure and the declines were developed through it using only 10% of the original volume and in only three weeks.
After years of testing different methods and resins from different competing companies, Palabora Copper decided to add Normet to its list of preferred suppliers to provide TamPur 116 and TamPur 125 when injection products are needed.
Because of the support Palabora Copper received from Normet Africa during all the application phases and the quick response when a problem arose, Normet has built a sustainable business relationship with the mine when it comes to problem-solving and technical recommendations.