When I reached the road leading to the Liushenyu coal mine in Qinyuan county, Shanxi province, around noon on Saturday, it had already been sealed off.

Ambulances waited nearby. Rescue vehicles rushed in and out. Police cordons marked the boundary between the outside world and a rescue operation unfolding deep underground — in tunnels rendered extremely dangerous by cave-ins, flooding and toxic gases.

A huge explosion rocked the coal mine at 7:29 pm on Friday. As of Saturday night, local authorities confirmed that 82 people had been killed and two remained unaccounted for. A total of 128 people were injured and taken to hospitals for treatment.

For rescuers at the site, every descent into the mine shaft was driven by one hope — to find signs of life.

Among those helping in the aftermath of the disaster is 54-year-old Guang Xinhai, head of the Shanxi Huayang mine rescue squad, one of China's national-level mine emergency rescue teams. Guang, who has more than three decades of experience in mine rescues, described the operation as exceptionally difficult.

After receiving the call late on Friday, Guang and his 67-member team set out for Qinyuan overnight and arrived at the site in the early hours of Saturday.

"We searched for more than eight straight hours, checking every possible corner," Guang said after coming out of the mine on Saturday. "We want to hold on to every little hope of life and bring the miners out as soon as possible."

Near the mine entrance, rescue personnel waited for their turn to descend to the affected area. As soon as one team returned above ground, another made its way down. Some rescuers, their faces blackened with coal dust, rested briefly on the open ground before heading for the next round of efforts.

One rescuer, still covered in dust after emerging from the shaft, said it was the largest rescue operation he had ever joined.

"As long as there is hope, we will make every possible effort," he said.

The difficult circumstances could be fathomed from the equipment being sent underground. Rubber boats, waterproof suits and other supplies were rushed into the mine to deal with flooded sections of the tunnel. Officials said the presence of toxic gases inside the mine shaft posed the risk of secondary disasters.

Villagers living nearby recalled hearing a loud explosion on Friday evening. Some miners managed to escape on their own, but others were not so lucky. Several survivors later spoke of thick dust and a deafening noise when the accident took place.

A retired miner who once worked at the mine also rushed to the site. Familiar with the underground layout, he said he hopes that his knowledge could help the rescue teams.

"I really did not want to see an accident like this happen," he said.

Rescue work continues at the site. Teams of rescue personnel are working around the clock in shifts and equipment is being sent to support the search.

"My greatest wish now is that the miners return home safely," said Guang, the rescuer.

His team has deployed robots underground to improve search efficiency and rescue safety.

Luo Wangshu in Beijing contributed to this story.