Problems with methane gas at south Wales's Tower Colliery were caused by the earthquake which struck last October, it has been revealed.

The colliery at Hirwaun in the Cynon Valley, south Wales, has spent more than £300,000 trying to tackle the problem.

But the management are optimistic that production can restart in the affected area in the New Year.

The new V40 face at Tower Colliery had been open just a few weeks when the earthquake struck mid and south Wales.

The epicentre was at Sennybridge in Powys and its effects were felt 25 miles away.

At first, workers reported only minor damage underground but later more serious problems developed and cracks caused by the tremor caused methane gas to flood into the area.

A three-mile pipe is being laid underground to ensure that the gas is siphoned from the pit.

Ironically just before the earthquake Tower launched a new scheme to control and pump methane gas from underground and covert it into electricity - cutting its energy bill by £500,000.

But the large amount of gas released following the tremor has been both potentially dangerous and damaging to the pit.

Sales at the pit are down by more than 20% and the colliery is finding it difficult to meet the demands of all its customers.

But Marketing Manager Phil White hopes production on the face will be back to normal by the end of next month.

"It opened up a fissure and allowed gas in from other coal seams outside Tower's control," he said.

"But we now have that under control and look forward to being back in production as soon as possible."