- 3 updates
Environment Agency Wales say that tests are being carried out to assess any damage that an orange coloured discharge found in the River Rhymney could have on water quality and wildlife.
They said samples will be taken and "if they confirm the pollution is caused by minewater, the Coal Authority will be asked to work with the Agency to try to improve the situation."
"Discharges of this type can occur many miles from the mine, as drainage tunnels were dug over long distances."
Environment Agency Wales say they have ruled out 'active industry' as the cause of the discolouring of a stretch of the River Rhymney near Caerphilly.
The Environment Agency Wales are investigating the source of an incident that has 'discoloured' a 6.5 mile stretch of the River Rhymney.
The river from Caerphilly to Machen has turned orange, possibly due to a discharge from an old mine.
The pollution is thought to have entered the river from a brook near Bedwas House Industrial Estate, and officers have been at the site since early this morning.
They say the exact source will be difficult to find due to the complexities of the underground mine workings.