March 4 (UPI) -- A Welsh utility company said workers excavating a trench for relocation of a pole on a customer's property made an unusual discovery -- a previously unknown medieval tunnel.
Western Power Distribution said members of the company's East Wales team were working in Tintern, in the Wye Valley, after a customer requested relocation of a pole on their property.
The workers were excavating a trench when they discovered what they initially believed to be a cave.
"I have been involved in other excavations where we have discovered old wells and cellars not shown on any plans, but nothing as exciting and impressive as this," WPD technician Allyn Gore said.
"Further investigation revealed it was a man-made tunnel around 4 feet in height," Gore said.
He said the tunnel runs under a sidewalk parallel to the Angiddy Brook, and appears to follow the brook's path.
Gore said the team manager called in a representative from Cawd, Wales' historic and cultural heritage service.
"He was very impressed with the sheer scale of the tunnel and quite fascinated to see it. In his opinion, it could possibly be linked to the iron work ruins previously discovered in the area," Gore said.
The Tintern Abbey iron works ruins, located nearby the site of the tunnel's discovery, date from the 1100s.
Gore said research into the area's history failed to unearth any mentions of the tunnel in ordinance survey maps dating back to the 1700s. He said it also does not appear in any public records.
WPD said work on the project was halted while Cawd archaeologists take over the investigation.
"For now, we have back-filled the trench and reinstated everything and we are planning an alternative route for the customer. It could take years before the investigations are concluded," Gore said.