A joint investigation initiated by South Wales Police, Wales Office and the Health and Safety Executive, have been launched to probe the Gleision Colliery tragedy. Investigators are working closely with specialist mine inspectors, and have already taken inside photographs of the pit as evidence.

"The investigation will draw on technical expertise from the Health and Safety Executives (HSE). HSE specialist mine inspectors are on site and are working closely with South Wales Police," the investigation team said in a statement.

"Initially the police will have primacy in accordance with the Work-Related Deaths Protocol agreed between the police, HSE local authorities and the Crown Prosecution Service. Later, it may be deemed appropriate for primacy of the investigation to be passed to HSE, as has happened in other incidents," the statement added.

The HSE has claimed that no enforcement notice on the Gleision Colliery was found in Mining Inspectorate's records. The investigation will spot the reason behind the fatal inrush of water that deluged the Swansea Valley colliery early morning of Thursday.

According to a Walesonline report, it was understood that explosives were being used to extract anthracite from the layer in the run-up to the disaster.

The use of explosive can also be a reason behind the deadly flood water in the mine shaft.

The law entails managers to keep surveyor, who will assess the area and provide maps of the workings in order to alert mine workers to work from the safe distance. The mine workers are not allowed to work in tunnels within 37 meters of any abandoned mine workings.

Regulation authorities state that mining is prohibited within the 45 meters of any direction, of a rock containing water or any abandoned workings which are not associated with mines.

In the early 20th century, some private companies were practicing notorious exercises of not submitting abandonment, leaving several old workings unknown.

"If you are going to undercut any contiguous workings, the things that are going to concern you are the vertical distance from any seam that might have been worked above you and might have been waterlogged," Walesonline quoted General Secretary at the British Association of Colliery Management Pat Carragher as saying.