Case study

Saltburn Gill mine water treatment scheme

Saltburn Gill mine water treatment scheme removes over 98% of iron from local waterways in East Cleveland, England.

Saltburn mine water treatment scheme
Saltburn mine water treatment scheme

Saltburn Gill is a narrow stream in a wooded valley in the area of East Cleveland, England. In 1999 a large, iron-rich mine water outbreak occurred which polluted Saltburn Gill and Skelton Beck, as well as discolouring a popular surfing beach.

Following initial work by the local Saltburn Gill Action Group and the Environment Agency, the Coal Authority was invited to help develop and build a mine water treatment scheme in the area, which removes the iron before it is discharged as clean water into the Saltburn Gill.

Saltburn mine water treatment scheme
Aerial view of Saltburn mine water treatment scheme before completion

Construction phases

Phase 1 works included the construction of two lagoons with cascades and a drying bed for ochre sludge. Mine water is pumped to the top of the aeration cascades, where it flows down into the lagoons. Over a period between 1 and 2 days, the majority of the dissolved iron precipitates and settles.

The ochre sludge is collected from the bottom of the lagoons and placed into the drying bed.

Saltburn mine water treatment scheme
Reed beds at Saltburn mine water treatment scheme

We monitored the results from phase 1, which showed the scheme was efficiently reducing the iron concentration.

We used this information to assist with the design of Phase 2 works, which included the addition of two more lagoons and a polishing reedbed. The reedbed acts to filter the remaining iron out of the water to a lower concentration.

History

The area of East Cleveland in England has seen large-scale deep mining for over 100 years. When local ironstone mining operations ceased in the 1960s, the dewatering pumps were turned off and removed. The workings subsequently flooded and iron-rich mine water rebounded, eventually reaching ground surface level.

The large mine water outbreak in 1999 quickly turned the stream bright orange and smothered the downstream ecology. A large ochre plume was occasionally formed as this water joined the Skelton Beck in Saltburn, and flowed into the North Sea.

Saltburn mine water treatment scheme
Discolouration of water at Saltburn Gill and Skelton Beck before the treatment scheme was in put place
Saltburn mine water treatment scheme
Discolouration on Saltburn beach before the treatment scheme was put in place

Saltburn Gill Action Group was established by the local community to raise the profile of the problem. The group worked with the Environment Agency to obtain funding to investigate options to clean up the pollution, and together secured the necessary funding from the Department of Environment, Food and Rural Affairs to address the pollution issue for the community. We worked with the action group and other stakeholders to develop the treatment scheme.

Saltburn mine water treatment scheme
Clear water at Saltburn Gill and Skelton Beck now the treatment scheme is in place

Our benefits assessment calculated that the total monetary benefit from preventing the discharge and treating the mine water is £10.5 million over 25 years.

Published 8 September 2017