The South African gold mining industry is currently under a lot of financial pressure due to a multitude of reasons. Many of these companies are also mining using systems first designed decades ago, that may no longer be applicable to the present-day mining environment. Mining companies have therefore started optimising and modernising some of their systems in order to reduce the operational costs of their mines.
Harmony Gold Mining Company is one such company and they are committed to modernising and improving the efficiency of all the systems across their mining network. To this end, in conjunction with ETA Operations, they have taken strides towards optimising the Compressed-Air Networks on several of their mines by reviewing the entire network, optimising the existing network and introducing new equipment.
The optimisation procedures, developed by ETA Operations and implemented as a joint venture between Harmony and ETA, were aimed at reviewing the design and function of the entire Compressed-Air Network in order to ensure that the network as it is today is still optimised for today’s mining environment. An example of the implementation of these procedures can be seen on Harmony’s Kusasalethu mine.
The review of the systems at the Kusasalethu mine revealed several sections of the Compressed-Air Network that were no longer optimised for current mining conditions. These included refuge chamber valves that could be forced and left open even when there was no emergency. This was a large waste of compressed air and could also be dangerous since prolonged usage could damage these important parts of the safety system. There were also several bypass pipelines that were not wide enough to accommodate modern mining airflows.
These sections were therefore reviewed and the infrastructure in the sections was either reconfigured, replaced or both in order to bring the systems into line with the needs of a modern gold mine.
“These changes presented several benefits to Harmony including an electricity cost saving of approximately ZAR100,000 per day. With a capital expenditure of only ZAR1 million for the entire optimisation project, this equates to the project paying for itself in only 10 days. The reconfiguring of the refuge chamber’s valves also brought a substantial safety benefit to the mine and the replacement of the bypass pipes allowed for even greater control, and concomitantly better production scheduling, when the bypasses were used.”
“Using the innovative cutting-edge optimisation process, the Harmony mining group has therefore significantly improved the Compressed-Air Network on their Kusasalethu mine and they have gained significant benefits to their electricity budget, their safety procedures and their mining productivity. However, the implemented are not only applicable to Compressed-Air Networks and can also be applied to any field in which large networks are used. As such there are plans to expand the rollout to other fields and other mines in order to gain even greater operational efficiency and savings.”