Heavy machinery can remove large amounts of material, but it cannot always operate safely in a confined underground space. In some situations, rescue specialists must rely on smaller equipment and carefully controlled manual work.
The physical conditions can also be exhausting. Underground rescue teams may face poor ventilation, dust, darkness, restricted movement, and long periods of intense concentration.
The trapped workers face their own dangers. Injuries, dehydration, cold temperatures, stress, and limited mobility can all complicate survival.
The excavator operator in Gwangmyeong was eventually rescued after approximately 13 hours underground. Reports said he had been trapped around 30 meters below the surface. He was conscious when reached and was taken to hospital for treatment.
His rescue was an important breakthrough, but the operation was not over. Another worker remained missing, and authorities continued searching through the damaged underground structure.
For the rescue teams, finding one survivor did not lessen the responsibility to keep looking for the other.
Chapter 3: One Worker Survived, Another Was Still Missing
The rescue of the excavator operator offered a moment of hope during an extremely difficult operation.
The worker, a man in his twenties, had reportedly been repairing an excavator when he went to get some water. During that brief moment, the ground collapsed and he fell into the underground debris.
He was trapped approximately 30 meters below the surface. Parts of his lower body were pinned beneath concrete slabs and other debris, restricting his movement.
Despite the conditions, he managed to contact rescuers using his mobile phone. That communication helped establish that he was alive and gave emergency personnel a vital starting point for the rescue.
The rescue operation required patience and precision. Firefighters and specialists worked to reach him while attempting to avoid disturbing the unstable material around his body.
According to reports published after the incident, rescuers were eventually able to make face-to-face contact with him. He showed signs of dehydration, and personnel provided him with drinks and food while preparing to remove him.
After approximately 13 hours underground, he was brought to the surface using a crane.
He was transported to a trauma center for treatment. Reports said he had suffered a fractured collarbone and dehydration, although his condition was not considered life-threatening at the time.
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The rescue was a remarkable achievement for the emergency teams. But the relief was incomplete.
A second worker, a man in his fifties, remained missing.
Authorities believed he had been inside or near a temporary container at the time of the collapse. Determining his exact location was difficult because the structure and surrounding debris had been heavily damaged.
The search continued for several days.
Rescue workers used heavy machinery, specialized equipment, and search dogs to investigate the underground area. They also removed large quantities of soil and sand while creating a route toward the lower section of the collapsed structure.
The operation was complicated by the risk of further ground movement. Officials had to consider the possibility that removing one section of debris could destabilize another.
On April 16, six days after the collapse, rescuers found the missing worker. He was pronounced dead, bringing the search to a tragic conclusion.
The outcome highlighted the human cost of underground construction accidents.
Behind every rescue operation are workers with families, responsibilities, and lives outside the construction site. A worker who enters a tunnel for a shift may be someone else's parent, partner, child, or friend.
For the families waiting outside, the uncertainty can be devastating. News that one person has survived may bring hope, while the continued absence of another can prolong an agonizing period of waiting.
The incident ended with one worker surviving and another losing his life. It was a reminder that even when rescue teams work tirelessly, the conditions created by a structural collapse can make a successful outcome impossible for everyone involved.
Chapter 4: Why Can Underground Construction Sites Collapse?
Underground construction is among the most technically demanding forms of civil engineering.
Before a tunnel is built, engineers must understand the geology beneath the surface. Soil type, groundwater levels, nearby foundations, buried utilities, and existing underground structures can all influence how excavation should proceed.
A tunnel that appears stable during one stage of construction may become vulnerable as more material is removed or as pressure changes around the excavation.
One important risk is the movement of soil.
When workers excavate underground, the surrounding ground loses some of the support that previously held it in place. Temporary support systems are therefore installed to help maintain stability until permanent structural elements are completed.
These systems may include steel supports, concrete linings, retaining walls, ground anchors, and other reinforcement methods.
If a support structure becomes damaged, overloaded, or unable to resist the surrounding pressure, cracks and deformation may develop.
Water is another major concern.
Groundwater can enter an excavation through cracks or weak areas. If water begins carrying soil particles with it, the surrounding ground may gradually lose strength.