Case study:River Seaton: Abandoned Metal Mines
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Project overview
| Status | In progress |
|---|---|
| Project web site | |
| Themes | Environmental flows and water resources, Habitat and biodiversity, Monitoring, Water quality |
| Country | England |
| Main contact forename | Hugh |
| Main contact surname | Potter |
| Main contact user ID | |
| Contact organisation | Environment Agency |
| Contact organisation web site | |
| Partner organisations | The Coal Authority (UK) |
| Parent multi-site project | |
| This is a parent project encompassing the following projects |
No |
Project summary
The Seaton catchment is heavily impacted by historic mining activity throughout its entire length, but especially in the upper reaches around South Caradon mine. The mine is located on the South Eastern edge of Bodmin Moor in South East Cornwall. It is cut through by the River Seaton, which is fed by groundwater as well as surface runoff during heavy rain events. Ore processing at South Caradon mine started in 1838, at which time the mine covered most of the south side of Caradon Hill, and finished in 1890. When South Caradon finally closed it left miners with no prospects of work anywhere else in the Duchy. Many went to England to find work in factories or coal mines, but large numbers emigrated to work metal mines all around the world.
From the remains on the site and documented history, it is known that the processing of material from the mine shafts was carried out within the River Seaton valley. River water from the Seaton was used in the separation process, and waste water with a high concentration of metal solutes, sand, and silt-sized particles, was discharged directly into the River Seaton. Processing of Cu bearing ore at South Caradon mine involved the heating, pulverizing and dissolving of metals and their compounds, resulting in release of Cu and Zn into the surrounding environment. The legacy of these processes is a proliferation of tips, disused shafts and 3 adit discharges which between them contribute high levels of Zinc, Copper and Cadmium to the river.
When water quality and flow data are combined, it is evident that the most important sources of Cu, Cd and Zn contamination in the River Seaton are Jopes Adit, and the '3 Adit Streams'. Although the 3 Adit Streams discharge from beneath a rock tip, the chemistry results indicate that the 3 Adit Streams and Jopes Adit discharges are related in terms of source. Tip run-off is an additional significant source of Cu, Cd and Zn entering the main stream, particularly in prolonged heavy rain conditions. The site is listed on the MINING WASTE DIRECTIVE INVENTORY since the wastes cause more than 500 metres of the river to be polluted.
Most of the mine site is designated as a Site of Special Scientific Interest (SSSI) since the high metal concentrations in the soil support specialised flora of rare mosses and liverworts. This is one of two sites in the world where the Cornish path-moss occurs. The Caradon Mining District is part of the CORNISH MINING WORLD HERITAGE site.
The Environment Agency are working with the Coal Authority to develop remedial options to address the pollution and return the river to good status.
Impact of the Jopes Adit discharge
Length of watercourse affected = 17km Average metal concentration: Zinc = 510ug/l; Copper = 1180ug/l; Cadmium = 1.5ug/l Average flow = 56 l/sec Load of Zinc discharged per day = 2.5kg Load of Copper discharged per day = 5.8kg Water body ecological status = Poor
Benefits of remediation
The River Seaton will be protected from a major pollution source Contribute towards achieving Good Ecological and Chemical status 912 kg of Zinc and 2,100 kg of Copper would be prevented from entering R Seaton every year
Monitoring surveys and results
Lessons learnt
Image gallery
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Catchment and subcatchment
Site
Project background
Cost for project phases
Reasons for river restoration
Measures
MonitoringHydromorphological quality elements
Biological quality elements
Physico-chemical quality elements
Any other monitoring, e.g. social, economic
Monitoring documents
Additional documents and videos
Additional links and references
Supplementary InformationEdit Supplementary Information
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