Haggs mine water treatment scheme

Information and updates on the Nent Haggs mine water treatment scheme in Cumbria, England.

The River Nent is the second most metal polluted river in England. This pollution, by cadmium, lead and zinc, comes from several different sources and the effects on water quality and aquatic life can be seen for 60km along the River South Tyne and in the Tyne Estuary.

One of the most significant sources of pollution is the Haggs adit, an abandoned mine water drainage tunnel.

To improve the environment for people and wildlife, the Coal Authority and Environment Agency are developing a treatment scheme to remove the metals from the Haggs adit mine water before they get into the river.

Following discussions with the public and other stakeholders, we submitted a planning application to build the treatment scheme on land between Blagill and Nentsberry in Cumbria.

Planning permission was granted by Cumbria County Council in June 2019. You can look through the planning application on the Cumbria County Council website, using the reference: 3/18/9001.

Search the Cumbria County Council website

The mine water will be captured at the adit portal in Nentsberry and taken to the treatment site in an underground pipeline.

The metals will be removed using 3 treatment ponds, then the water will pass through a new wetland before being put back into the River Nent.

We have appointed a contractor to build the scheme, I&H Brown Ltd.

We have also completed all of the land agreements we need to build and operate the scheme.

2022 work schedule (November 2022 update)

Our contractor, I&H Brown, has made good progress building the mine water treatment scheme during 2022 although it will not be completed until spring 2023.

First the site cabins will be put up at the treatment ponds. Then we will start to remove the surplus soil mound that has been stored during the shutdown period, which will take up to 6 weeks.

Construction schedule November 2022 to spring 2023:

  • November to December 2022: completion of the compost treatment ponds, reed beds, mine water distribution pipelines, and odour control tanks and building
  • January to April 2023: installation of mechanical and electrical equipment (primarily inside the building)
  • Spring/summer 2023: installation of mine water pumps, placement of the reactive media which will remove the metals and commissioning of the scheme

Biodiversity improvements at site 38

During August and September we completed work to enhance the biodiversity of the Horse and Wagon field that contains the pumping station. This should encourage wildlife to return to the field and create an informal nature reserve for the community to use.

Trees, shrubs and wetland vegetation will be planted in November.

The site 38 works are being co-funded by the Water and Abandoned Metal Mines (WAMM) programme and Northumbrian Water. This is one of several projects Northumbrian Water is supporting across the South Tyne catchment, aiming to improve river water quality and habitats, support biodiversity, and address the impacts of climate change.

Completed works

Since we started construction in July 2020, the following work has been completed:

At the pumping station (site 38):

  • construction of pumping station, including installation of mechanical and electrical equipment
  • improvements to surface water drainage along the A689 from Haggs adit to site 38
  • improved surface water drainage across site 38

At the treatment ponds (site 4):

  • completion of the 3 mine water treatment ponds and 2 reed beds
  • land drainage to manage surface water on site
  • final outfall to the river from the treatment system
  • improvements to the Isaac’s Tea Trail footpath alongside the River Nent adjacent to the site

Mine water pipeline installed:

  • from the Haggs adit to site 38, mostly in the A689 carriageway
  • between site 38 and the junction between the A689 and the B6294, including by directional drilling under the river just downstream of Nenthall Bridge
  • from Nenthall to site 4 along the A689 and B6294 carriageway
  • repairs to the A689 and B6294 road surfaces were carried out during summer 2022

View Nent Haggs mine water treatment scheme maps

View past updates relating to the Nent Haggs mine water treatment scheme

Read more about the work of the Water and Abandoned Metal Mines programme


Maps and drawings relating to the Nent Haggs mine water treatment scheme.

Published 25 February 2016
Last updated 14 November 2022 + show all updates
  1. The 2022 work schedule has been updated

  2. Work schedule for March to November 2022 added

  3. Work schedule for July to September 2021 added

  4. Updated work schedule with information for April and May 2021

  5. Added schedule of works, with more detailed plans for the initial 12 weeks between July and October 2020

  6. Building contractor details added to the page.

  7. Updated to include information about anticipated construction date and to remove out of date information

  8. Link for the interactive map of proposals for cleaning up mine water discharges into the River Nent added

  9. Removed information about out of date proposals

  10. First published.