Case study:Rookhope Burn: Abandoned Metal Mines
Project overview
Status | In progress |
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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 |
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Project summary
The Rookhope Burn is in the North Pennine orefield, and mining has been carried out in the valley for over 200 years - mainly for lead and fluorspar along with small deposits of copper and iron. This has left a legacy of mine water drainage adits and spoil heaps throughout the area. The last working fluorspar mine in the north of England, at Grove Rake, closed in 1999. In 2007, a new mine water breakout occurred, thought to be due to a blockage within the Tail Race level, which drains the abandoned mines further up the valley. This caused a large hole and a new discharge near to the old Rispey mine.
Water quality monitoring by the Environment Agency found there were high concentrations of cadmium, lead and zinc in the Rookhope Burn where it joins the River Wear. These high metal levels damage river life (insects and fish) and exceed the Environmental Quality Standards (EQS) for the Rookhope Burn, meaning that the watercourse isn't achieving the 'good status' for water quality that is set out in our Northumbria River Basin Plan. We found there are inputs of metals from disused adits and diffuse sources along the whole length of the Rookhope Burn but the largest single source is from the new breakout, which if cleaned up could improve over 8km of river. Fish surveys carried out by the Environment Agency in 2009 found reasonably good numbers of brown trout in the upper reaches of the Rookhope Burn and downstream of Rookhope Village but very poor numbers in the middle section - this was attributed to the impact of the Rispey mine discharge.
We're continuing to investigate and monitor the water quality in the Rookhope Burn, and with funding from Defra we set up a partnership with the Coal Authority and the North Pennines Area of Outstanding Natural Beauty Partnership (AONB) to look at options for removing the metals from the Rispey discharge to improve the water quality of the watercourse. Newcastle University are carrying out trials of treatment technologies which we could use to remove the heavy metals from the Rispey discharge, preventing the problem at the source and helping the Rookhope Burn to meet the EQS and return to 'good' ecological status.
• The Rookhope Burn fails its EQS for cadmium, lead and zinc. • In times of low flow the Rispey discharge is contributing more zinc than reaches the River Wear indicating metals are being retained in the river sediments. • When the river flows increase, a greater load of metals reaches the end of the catchment than enters the Rookhope Burn from the Rispey discharge. Additional metals are being washed into the river from mining spoil by rainfall, and from mobilising the metals previously retained within the river sediments. • Treating the mine water discharge to remove the metals could enable 8km of river to pass the EQS and help the waterbody improve to good ecological and chemical status.
Impact of the minewater discharge • Length of watercourse affected is 8km (one water body) • Average metal concentration: Zinc 1.5 mg/l Cadmium 1.5 ug/l • Average flow 35 l/sec • Load of zinc discharged per annum 1.5 Tonnes • Water body ecological status is Moderate
Benefits of remediation • The River Wear will be protected from a major pollution source • We are using compelling evidence to drive our decisions • We are developing partnerships with important stakeholders and using our position as an influential advisor to deliver shared environmental outcomes • Contribute towards achieving Good Ecological and Chemical status • 1.5 Tonnes of zinc would be prevented from entering River Wear every year
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