Dave Cooke The Coal Authority
WAMM! Partnership (no Coal!) main funder and programme owners lead on catchment characterisation, impacts and priorities. lead on scoping, feasibility, design, build and operation of schemes.
WAMM! Metal Mines • 105 Water bodies affected by abandoned metal mines • 1500km of rivers impacted by metals causing good status failures for chemicals • 11% of groundwater bodies in poor status. • 7 of 11 River Basin Districts affected. • Fe, Ni, Pb, Cd, Cu, Zn, Al, Mn …all mined • Approach driven by WFD, feeding into RBMP , but no legal liability for past operators / current owners (of abandoned metal mines).
WAMM! Mine Waste Directive Inventory
WAMM! and Contaminated Land Traditional contaminated land terminology: Characterisation Scoping and Optioneering Treatment Techniques Diffuse Sources Dissolved Sources Monitoring and Improvements
WAMM! Characterisations and CSMs EA Characterisation Reports Monitoring and Assessment Focus Diffuse and Dissolved Sources and Mechanisms Prioritisation and Cost Benefit Analysis
WAMM! Conceptual Models
WAMM! Conceptual Models
Optioneering – the WAMM Toolbox Part of Scoping and Feasibility Constrained by: Geographical and Environmental Limits Mine water and spoil geochemistry Financial Political and competing policy objectives
WAMM! Works to date 75 individual waterbodies investigated, with a current • portfolio of 40+ active projects across England Because no legislative driver, schemes are assessed on the • basis of estimated benefits to cost ratios: Average for first 18 schemes B:C 3 • Top 6 schemes B:C >5 •
WAMM! Treatment Techniques Water (Dissolved Sources): Reaction, absorption and filtration / settling Reaction can be direct (HDS type water treatment) or indirect (VFP / VFR / HFR) Absorption (activated carbon type) Electro-precipitation (electro-chemical reaction). All based on the concentration of metals into the solid phase (with subsequent disposal / recovery?!).
Treatment continued Solids (Diffuse sources): Typically, deposited mine spoil, erosion products (river sediments), mine processing residues. Traditional engineering techniques applicable: Containment, capping, surface water management, erosion protection. All about prevention of leaching and physical transport of solids into the water course.
WAMM! Case Studies (with the promised photos) Saltburn Pump and Treat (Aerated Iron Precipitation) Force Crag Passive Treatment (Compost VFP) Nent Check Weirs – Dredging and New Build (Dig and Dump!) Foreshield Shaft protection (Gabion Wall) Carrshield Tailings Dam (Retaining Wall, Capping and Interceptor Drain) Wheal Jane (HDS and Clarifiers)
WAMM! So far so good - Saltburn Remediation of Ironstone Mine discharge polluting stream, SSSI and bathing beach. £10.5 million benefits into the local economy over the next 25 years Removes in excess of 98% of metals. (100 t Fe/year) Removed the risk of a catastrophic mine water break out
WAMM! So far so good – Force Force Crag Crag Worked for zinc, lead and barytes from 1835 until 1991 Pollution affecting local becks, river and Bassenthwaite lake. High levels of zinc, cadmium, lead and copper A full scale passive treatment scheme now operational. Removal of >95% of Metals
Force Crag and Coledale
WAMM! So far so good – Nent Check Weirs Environmental Outcomes River Nent – Dredging existing check weirs (Nenthead) Metals removed: 20 – 30t Zn, Cd, Pb Up to 60km of river improved, River Nent - New check weir (Nenthall) contributes to Tyne estuary sediments Metals removed: forecasted 1.4t Zinc/yr Scheme cost : Up to 60km of river improved, contributes to £487k Tyne estuary sediments (aim to decrease Scheme benefit: £3 from ~127t Zn/yr to <50t/yr) - £10m (25 yrs) Scheme cost: £320k Whole life cost: £1.1m Scheme benefit: £3 - £10m (25 yrs)
WAMM! So far so good – Foreshield and Environmental Outcomes Carrshield River Nent – Foreshield shaft River West Allen – Dressing floor diffuse pollution prevention Metals removed : not quantified Cost: £187k Metals removed: not quantified Benefits: prevented river eroding metal- Cost: £450k rich soil and being diverted into the Nent Benefits: together with Carrshield tailings dam, Force Level; protects calaminarian SAC contributes up to 5% of Zn entering Tyne estuary 18
WAMM! So far so good – Carrshield Tailings Dam River West Allen: More than 40km of river polluted with metals • 6.5km downstream: up to 126x zinc EQS (52x cadmium) • 27km downstream: up to 8x zinc EQS (6x cadmium) • Up to 25% of zinc entering Tyne estuary (sediments) are from West Allen • Fish and river flies (invertebrates) impacted for several km • Environmental and economic benefits >£30m over 25 years • Barney Craig mine water: key source of metals • Carrshield tailings: significant risk of imminent collapse • 48,000 cubic metres containing >60 tonnes zinc and 47 tonnes lead • Scheduled ancient monument (Victorian wall, tailings in 1950s) • Mining Waste Directive inventory: causing serious environmental harm (run-off) • 19
Carrshield Downstream
Wheal Jane Treatment Plant
Wheal Jane Consequences
WAMM! Future Plans Nent Haggs Passive Treatment Scheme (Water Transfer and VFP) West Allen Check Weir (Sediment retention) Coalcleugh (Surface water management and floodplain lowering) Ashfoldside Drainage Interception (Surface water management) Gwindra Pilot Scheme (4 pond gravity VFR) Tees Swale Diffuse (Green engineering and erosion control) Cambokeels Passive Treatment (In-situ VFP) 23
Nent Haggs Visualisation
WAMM! Future Plans WAMM sites in Yorkshire
WAMM! Headlines Environmental Outcomes Wheal Jane Saltburn Force Crag Water treated: 0.82million m³ Water treated: 5.34million m³ Water treated: 65,000 m³ Metals removed: 102t of Fe Metals removed: 600t Cd, Ni, Zn, Metals removed: 175kg of Zn 2 km of river improved. Cu, As, Fe 10 km of river improved. 8km of watercourse improved, Fal Bassenthwaite Lake SAC now Estuary SAC protected meets EQS
WAMM! Ongoing
Thank You
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