September 20, 2023
The future of underground charging
Safety is a number one priority when working underground. In charging operations when explosives are involved, there is really no room for error, which is why Normet are constantly developing their offering, explains Anssi Mykkänen, Charging Product Line Director.
Safety and productivity through mechanisation and automation
Mines are getting deeper – in Finland we have Europe’s deepest at 1.5 kilometres, but today mines around the world are going as deep as three- or four-kilometres underground. At such depths, focusing on improving operator safety and the underground production setting is key. In that environment today, an operator presence is still necessary, but we’re moving towards full automation.
If we think about the charging process, it is quite complicated and traditionally requires multiple workers to carry it out properly. Person lifters are required to move the operator to the correct place where they can manually insert the detonator and priming unit.
Through mechanisation and ultimately automation we can improve these processes. We can measure explosive consumption, pressure, sensitizing, mixing ratios and other key information. All of this is done to improve safety and efficiency.
Changing technologies and regional concerns
Naturally, our product offering supports these principles. Although ANFO charging was the industry standard for decades, the latest emulsion charging technology from Normet provides many benefits, in part thanks to mechanisation. With emulsion charging, our customers can realise total cost savings in face charging of up to 25%, partially due to a reduction in power consumption of up to 200%.
Also, emulsion charging is ergonomically superior. There is less heat, less noise exposure, and cleaner air for operators. The transport and storage of non-explosive raw material is easier and safer. Because the same explosives are used in all bore holes, logistics are simpler. And the overall process is more environmentally friendly with less nitrate emissions and can be performed by one or two operators instead of many. Emulsion charging also makes following procedures easier thanks to better blast control, rock fragmentation, cleaner detonation fumes and reduced waste explosive. Again, safety and efficiency are crucial.
Another interesting aspect of this equipment we need to consider is regional differences. For example, Normet’s explosives charger Charmec MC 605 is customised for different countries depending on local regulations. The base unit is the same, but there are, added person lifting safety features, overload protection, detection and prevention systems, and so on. In India, for example, regulations require an operator presence switch that the operator must keep pressing to stop the machine shutting down. Australia, Europe, and other territories have other rules.
Facing challenges and delivering value
Ultimately, the final target is fully automated machines for explosives charging, concrete spraying, or any other underground process, where the operator drives and controls the machine away from the workface, perhaps from outside the underground mine. The processes themselves are already very efficient. Of course, they may be improved in the future, but if we can maintain efficiency with remote operation then that would be a huge step forward. And solo robotic machinery will face a big challenge to last long in an underground environment because of the high moisture and salt content, chemicals, explosives, rock bursts and so on.
It is very challenging, especially in relation to charging and blasting. Compared to other processes, charging requires a high degree of accuracy. The machine has to, at a bare rock face, identify the correct locations for the charges, drill holes of a suitable size, and insert charges. It must be accurate enough to locate 50 mm boreholes in a six-by-six metre face. That’s a real challenge and explains why full mechanisation and automation is so demanding.
In the end, business is between people, and we aim to serve our customers. We provide cost and efficiency benefits throughout our processes, and charging and blasting are no different. We work with our customers over decades to improve all areas of our businesses. For the operators there are practical benefits such as less heat and pollution while working. On the project scale, for owners, we can help to reduce costs considerably in, for example, ventilation costs through battery-electric vehicles – which, by the way, can offer better underground performance today than diesel vehicles. This demonstrates our whole-process knowledge and philosophy once again.
As we continue to improve underground charging processes through automation, training, and product development, we always engage with our customers to find the best solutions to their needs, in all Normet processes.
About the author
Director, Charging Product Line