Rescue workers search for two miners trapped underground through an endoscope at a zinc mine in Bonghwa, 244 kilometers southeast of Seoul, Nov. 3. Yonhap

Rescue workers on Thursday began to search for two miners trapped underground for nine days by drilling a hole and inserting an endoscope.

They have been isolated in a vertical shaft about 190 meters underground at a zinc mine in the county of Bonghwa, 244 kilometers southeast of Seoul, since it collapsed on Oct. 26.

Rescue workers managed to drill a hole Thursday morning to reach their estimated burial point 170 meters underground, the local fire department said.

They began a search operation using an endoscope inserted into the hole with a diameter of 76 mm. They also used a sound detection device.

The miners, both surnamed Park, are 62 and 56 years old, respectively.

"We are here to rescue you. If you hear my voice or see a light, please come slowly to the light and shout," a rescue worker said through the hole.

After failing to detect any reaction, they moved the drilling machine to a location 168 meters underground and continued the search. (Yonhap)