A £1.4m WATER treatment project has been launched at the National Coal Mining Museum.
The museum - formerly the Caphouse Colliery at Overton, between Huddersfield and Wakefield - has installed a new environmentally-friendly system of treating water which collects on its coalfields.
The scheme was officially opened by former Kirklees Council leader Sir John Harman, chairman of the Environment Agency.
Guests were welcomed by museum chairman Baroness Lockwood.
Also attending was John Harris, chairman of the Coal Authority, which played a leading role in supervising and funding the scheme.
Yorkshire was once known for the orange water that streamed out of its pits - water contaminated with ochre from the iron released by mining.
Collieries once pumped out the water from their pits and treated it, but the closure of pits means more drainage problems and less treatment.
Water used to be pumped from the pits at Caphouse Colliery and treated in settling ponds with lime.
Tankers collected the sludge, which was dumped in landfill sites.
But the museum decided this was very bad for the environment and set about creating the new scheme.
There are now four more settling ponds, making a total of six. There is also a balancing chamber and a reed-bed system, which will both remove ochre from the water without harsh chemicals and the need to dump in landfill sites.
The aim is to harness the power of nature to clean and recycle the water.
The museum's nature trail has also been extended around the new ponds.
Dr. Margaret Faull, the museum's director, said: "The National Coal Mining Museum for England is proud to be involved with the Coal Authority in such an innovative project, which sets a standard in environmental management and an example for mining communities around the world."
The event was also attended by Paddy Tipping, MP for Sherwood in Nottinghamshire, who lobbied Parliament on behalf of the museum to help get the project off the ground.