Project Overview

About 200km of rivers in Teesdale and Swaledale are polluted by metals released from long-abandoned metal mines in the headwaters. Some of these metals are washed into rivers from the wastes left behind by the miners. The Tees-Swale Diffuse Metals Project is beginning to address this polluting legacy of Britain’s industrial past with funding from the Department for Environment, Food and Rural Affairs (Defra) and the National Lottery Heritage Fund. This work is part of Tees-Swale: Naturally Connected programme, led by the North Pennines AONB Partnership in collaboration with the Yorkshire Dales National Park Authority, funded largely by the National Lottery Heritage Fund.
The diffuse metals project is led by the Yorkshire Dales Rivers Trust working with the Tees Rivers Trust as part of the Water and Abandoned Metal Mines (WAMM) programme. We are working with the North Pennines AONB Partnership and local landowners and farmers including the Eggleston Estate (Neamour Holdings) and Raby Estate. The WAMM programme is a partnership between the Environment Agency, the Coal Authority and Defra. It aims to deliver the Government’s statutory target to halve the length of rivers polluted by harmful metals from abandoned metal mines by 2038.

Little Eggleshope

Metals like lead, cadmium and zinc are polluting the Little Eggleshope Beck, a tributary of the River Tees, as surface water is eroding the old mine wastes. 

The riverbank is being strengthened by installing 300 metres of block stone wall (‘revetment’) which will limit erosion. In addition, the highly contaminated mine wastes next to the beck are being regraded. Approximately 1000 tonnes of stone and 600 tonnes of clay are being used. Work is scheduled to be completed in Autumn 2023.


Great Eggleshope

Mine wastes cover about 6 hectares of the former Wiregill lead mine in Teesdale.  Metals are being washed out of these wastes and polluting about 8km of rivers. Research trials by the WAMM Programme near Alston show that one way to address this problem is to encourage plants to grow as this decreases infiltration of rain.


We are testing different soil amendments, including biochar, and seed mixtures on 0.8 hectares of highly-contaminated material at the former “dressing floor” where the ores were crushed and processed. Initial results are promising, and we hope to improve biodiversity, particularly of rare metal-tolerant ‘calaminarian’ plants. 

Marl Beck

The large areas of mine wastes at the former Lodge Sike mine in Teesdale pollute more than 4km of Marl Beck and other rivers. Metals are being washed out of the fine-grained processing wastes left by the miners in the 19th Century and harming river wildlife.


We have reinstated former drainage channels to divert clean surface water away from the metal-contaminated wastes. In 2022, we brought in 1500m3 of clean subsoil from Raby Castle, and in 2024, we will spread this over the highly metal-contaminated mine wastes. This will help encourage vegetation growth, increasing biodiversity and reducing the risk of metals being washed into the rivers.