Liu Hui repairs equipment at the Wanglou Mine in Jining, Shandong province. [Provided to China Daily]

With his eyeglasses and fair skin, Liu Hui does not look like a typical coal miner when he is off duty, but he has worked underground for nearly four years.

The reason for the 29-year-old's light complexion is the limited exposure to sunlight he has on a daily basis.

"Sunshine is a luxury to me," said Liu, who began work at the Wanglou Mine in Jining, Shandong province in 2012 after graduating from Shandong University of Science and Technology with a master's degree in mining engineering.

Two years later, Liu was appointed head of the 52-strong "undergraduate team", which was created in 2011.

Well-known for innovation among the 1,500 miners who work at Wanglou Mine, the team has been credited with saving the owners, Shandong Energy Group, around 7 million yuan ($1 million) annually by developing new techniques.

Xiao Qinghua, head of Wanglou Mine, said members of the undergraduate team have the ability to understand drawings and English manuals that can help them improve and repair machines, in turn saving on costs.

"Reducing costs is an efficient way of widening our profit margins against the background of a sluggish coal industry," said Xiao, adding that more than 90 percent of coal producers are suffering losses at present.

The undergraduate team works three shifts round-the-clock, with Liu taking the day shift. He gets up at 5:30 am and meets with his teammates half an hour later to analyze the conditions they might face underground.

At 6:40 am, the day shift members put on their kit and gather around in a hall at the mine's entrance.

Safety equipment is checked before they prepare to board the "cage" for their descent underground. "Safety is the most important thing for us," said Liu, pointing to the posters dotted around the hall with slogans such as "Always keep safety in mind".

"We have advanced machinery to ensure our working environment is safe," he said.

According to Xiao, the undergraduate team has not had a single accident in the past five years. He believes it is hard work, not safety concerns, that scares college and university students from considering mining as a career.

"Around 20 percent of undergraduate miners give up because they can't bear the hard work underground," Xiao said.

Liu agreed, saying: "The work of collecting coal underground is much harder than I expected".

"The first day I went down the mine, I just didn't want to move forward. The high temperatures made me sweat all day and the noise drove me crazy. I was looking forward to getting out of the mine every minute I was down there," he said.

"But as long as you hold on for the first year, you will get used to it."

Meng Qingxin, 29, joined the undergraduate team in August and was unsure if it was right for him at first.

"But I found the field work was a good way to test and improve what I learned at college, so I preferred to stay," Meng said.

The challenge of mining is also what keeps Liu in the industry, despite the negative effects its current slump has had on his wages.

"Every day is a fresh test for us, as we are digging deeper and frequently meeting new challenges. I still need to learn more," he said.

"I like the feeling when I solve new problems using the experience I gained in the field and the knowledge I learned at school."