A RUGBY club had a giant shock when an eight-foot long sinkhole opened on their pitch to reveal a 100m deep mineshaft beneath.

Under 10s and 13s had played games on the pitch at Nantyglo RFC’s Banna Park ground a mile south of Brynmawr just days before the sinkhole was found during routine maintenance.

And the ground, used for 60 years without any problems, had to be cordoned off while mine experts were brought in to investigate.

Home matches have been moved to Brynmawr Comprehensive School’s ground for the rest of the season while Coal Authority investigators work to fill the shaft, which was discovered underneath the try line and was part of the long-closed Cokeyard Colliery.

Nantyglo RFC chairman Russel Davies said: “We were very shocked when we heard about the sinkhole and we were also very worried about the ramifications it could have on the club and the wider community.

“It was a great relief to hear that the investigations had been completed and that they had begun the repairs, as the field means so much to people, because it is so well used.”

A large section was dug out by a digger before work began back-filling it with more than 2,000 tons of spark-proof stone.

Russell added that when they saw how deep the hole was their “jaws just dropped”.

It’s believed that the hole was created over years by rain washing away the soil used to fill the shaft in.

“We have to say a big thank you to Brynmawr School for having us, as well as the local council and Coal Authority for working around the clock to get this sorted,” added the club chairman.

Work is expected to take four weeks and the shaft will finally be secured with a reinforced concrete slab.

A Coal Authority spokesperson said before work started: “Our investigation into a ground collapse at Nantyglo RFC in Wales has revealed it was caused after material settled in a 19th century coal mine shaft.

“The site has been made safe and our engineers will design a permanent solution.”

Cokeyard Colliery was abandoned in 1889, but reopened in 1927 for three years before being closed for good and filled in.