Sunny disposition

In addition to reducing the number of workers, the systems have shortened the time miners have to remain underground.

Meng, from the Gaozhuang Mine, said that he is now always in a good mood, as he has time to enjoy the sunshine.

"Years ago, I went to work underground early in the morning before sunrise, returning home after sunset. I seldom saw daylight," he said.

"With a tough working schedule and little sunshine, I felt life was so boring and exhausting. I didn't have time to take care of my family, and my wife regretted marrying a miner."

In 2017, the Gaozhuang Mine began to install automated facilities. Before the machinery was introduced, Meng and his colleagues had to carry heavy picks and dig coal from tunnel walls. Now, they operate automated drilling machines.

Miners also used to carry large sacks of coal waste on their backs, but now machines place the waste on conveyer belts, which carry it to the surface.

"We just click a button to start all the operations, including tunneling, cutting coal and transportation," Meng said.

He added that 30 workers used to be required at the coalface for one shift, but now only seven are needed.

The machinery also means that employees such as Meng work just six hours a day. "I get to spend every weekend playing with my two children. It's impossible not to remain in a good mood," he said.

In 2017, the Fucun Mine in ­Jining, Shandong, which is also owned by the Zaozhuang Mine Group, became the first in China to cancel underground night shifts.

No workers are sent into the shafts after midnight, the time previously when a new shift began.

Tunneling, power supply, transportation, water drainage and ventilation at the mine are all remotely controlled from the surface.

The colliery's deputy manager, Wang Shikui, said miners who are no longer required to work underground are now employed at plants built to maintain the new facilities.

Reporter Zhao Ruixue (right) at the Baodian Coal Mine. [Photo provided to China Daily]

Immediate warnings

At the Jiangzhuang Coal Mine in Zaozhuang, water levels in different areas of the pit are monitored through a video surveillance system. Constant seepage from rock formations results in water accumulating, which could cause flooding.

Yu, from the Shandong Administration of Energy, said, "It's difficult to monitor workers and machinery around-the-clock, but the smart system can help with this and send immediate warnings to us."

At the Baodian Coal Mine in ­Jining, which is owned by the ­Yanzhou Coal Mining Co, part of the Shandong Energy Group, an underground 5G network is in operation.

Niu Qingjun, a shift leader working at the coalface where the system is installed, said the new network's high-speed transmission enables workers on the surface to control mining equipment over 500 meters underground with more precision than previously.

The network is resistant to explosions and damp, Niu said, adding, "It can also resist electromagnetic interference caused by equipment used in the mine."

In Shanxi, the Yangquan Coal Industry Group installed a 5G network at one of its mines in May.

Wang Guofa, an academician from the Chinese Academy of Engineering, said: "The 5G network is the new highway for smart mining. It is ushering in a total revolution for the ancient industry of mining."