Authorities closed a section of Kennon Road in Baguio City temporarily after motorists discovered a large hole that officials identified later as a collapsed tunnel from an old mining operation, not a sinkhole.

The damage was discovered early morning on Monday, February 2, 2026, in Barangay Wabak where residents and drivers reported that a vehicle almost fell into the hole. Photos and videos circulating online initially raised fears of a sinkhole.

The Mines and Geosciences Bureau (MGB)–Cordillera clarified that the collapse was caused by a failed adit, or horizontal tunnel, from a small-scale mining site beneath the road.

“Napu-form ang sinkhole through solution and dissolution of limestone. The area hindi naman ina-underlain ng limestone. Just below the road, there is an adit—adit of small-scale mining activities,” Raymanne Mabazza, supervising geologist of MGB-Cordillera, said.

MGB said the tunnel was part of an abandoned mine that had been ordered closed in 2019. Signs of ground subsidence were also observed in sections of the road nearby, prompting further technical assessment.

Police cordoned off the lane affected and closed it temporarily to traffic, causing congestion, especially for vehicles exiting Baguio City via Kennon Road.

MGB recommended sealing the abandoned tunnel fully to prevent further collapse.

“Sana i-block, i-backfill ’yung kabuuang binutas nila dati,” Mabazza said.

The Department of Public Works and Highways–Baguio City District Engineering Office immediately began embankment work at the site. Crews widened the affected area by several meters before filling it with gravel and debris and sealing it with concrete.

MGB said this was the first collapsed adit discovered in the area in more than a decade. Authorities said they will continue to monitor the site and nearby road sections for any further ground movement.