Dual-frequency 5G networks for smarter coal mining

As a result, multiple 5G applications have been realised at Dahaize, including 5G drones, unmanned driving and mining, automated transport, remote industrial controls, precise personnel positioning, and robot system clusters. The electromechanical chamber (the central power distribution room and central pump house) and main haulageway were equipped with 15 sets of 5G mobile inspection robots to enable real-time backhaul of super HD video, audio, and infrared imaging data from on-site devices as well as early detection and pre-warning of device failures.

Robots are equipped with multiple parameter sensors (CH4, O2, CO2, temperature, and humidity), dual-spectrum PTZ cameras, pickup intercoms, and obstacle-avoidance lidars, and support 5G dual-frequency transmission. Inspection devices are built with 5G modules, which can communicate with the base station set in the chamber via the 5G wireless network. On the surface, a remote-control station is in place to respond to data transmitted via the 5G industrial network.

The design of the underground video AI system is based on cloud-edge-terminal coordination. The terminal side collects videos and uploads to the edge side, and receives control commands from the edge side, which conducts video analysis and reasoning. Then, it reports results to the cloud management platform, and sends control commands to the terminal side. The cloud side performs algorithm training and management functions, delivers trained models to the edge side, and manages and dispatches intelligent computing units on the edge side.

This enables intelligent supervision of the fully-mechanized mining face – including abnormality detection on the main transport belt; behavioural monitoring of personnel; regional access management; intelligent control of air doors, electronic seals, hoist heads and tail rope detection; AI identification for the coal selection plant; and underground intelligent traffic control, among other AI-assisted functions.

In the challenging underground conditions of coal mines, however, there is limited space and practical scope for the installation of complex equipment; Dahaize however has shown how this can be achieved with measurable success. Based on the accumulated project experience, a 700MHz base station with built-in safety features was developed. Native electric explosion protection measures for instance are used, which intrinsically enhance the safety of the 5G network, and are 80% smaller and 90% lighter than common explosion protection equipment.

No explosion proof box is therefore needed for underground projects, meaning no spark risks, and project costs can be lowered by 60%. Super diffraction and anti-interference performance enables full 5G coverage at a single station on the mining face, totally eliminating the need to install cable networks on the mining face. Full underground 5G coverage at low cost is therefore realised, and network construction costs also greatly reduced.

Seamless connection between the private and public networks has been accomplished, so miners underground can use the mobile service of China Broadcasting Network Group to communicate via the private network with internal lines above-ground, and communication with subscribers of public networks above-ground is also supported. By using a single phone card, then, miners can work more efficiently and keep connection with loved ones outside of the coal mine.

The project at Dahaize has reduced the need for 4 shearer drivers, 6 hydraulic support workers, and 5 clearance staff to one remote control personnel and one safety inspector. The establishment of a 5G robot cluster with 15 robots has contributed to 12 intelligent inspection and collection subsystems and 20 unmanned positions, reducing 90 personnel while cutting coal cost by RMB 12 per ton and labour cost by RMB 20 million per year.

The overall network architecture, transmission jitter and stability all outperform traditional 5G single-frequency networks, while quality of service was improved across intelligent applications such as 5G VoNR, mining, transportation, ventilation and safety, laying solid foundations for intelligent application system clusters. Previous reservations about the viability or ROI of 5G in coal mining can now therefore be set aside.

What are the next steps?

Dahaize Coal Mine will continue to develop its 5G capabilities, including its virtual interaction application, robot clusters, unmanned driving, intelligent wearables, intelligent inspections, smart shearers, and intelligent tunnelling machines. It will also continue to promote the integration of new 5G infrastructure and Industry 4.0, and provide support for the comprehensive reform and digital transformation of coal mines.