Plenmeller is an opencast coal site near Haltwhistle and approximately 40 km west of Newcastle. The site is in an area noted for its important upland plant communities.
Case study date
2010
Size
458.00ha
Location
Northumberland
Operator
UK Coal Mining Ltd
Mineral Planning Authority
Northumberland County Council
Mineral Type
Coal, Opencast
Habitat(s) Created
Upland Heathland, agricultural land and woodland
Restoration / Priority Habitats
Upland heath
Partnership Working
UK Coal Mining Ltd
Key Issues
Carbon Storage
Public Benefits
Open access
Background
Plenmeller is an opencast coal site near Haltwhistle and approximately 40 km west of Newcastle. The site is in an area noted for its important upland plant communities.
Coal has been extracted in the Plenmeller area since the 19th century. In 1987, planning consent was issued to British Coal (now UK Coal Ltd) for opencast coal extraction, and operations started in 1988.
Planning history
Following a public enquiry in 1987, planning consent was issued on the condition that approximately 190 ha of the site were restored to incorporate cotton grass, mat-grass, heath rush, heather and sphagnum moorland plant communities.
There was also a requirement to establish trial plots in 1990 to research and develop restoration techniques that would inform best practice in establishing target plant communities in subsequent phases of restoration. These trials provided a starting point for field-scale work carried out by Environmental Advisory Unit (EAU) of Liverpool University, ADAS and the Soils Advisory Group. The habitat creation outlined here summarises this work.
Habitat creation details
The Plenmellor site has been restored to upland habitats, agricultural land and woodland. UK Coal worked collaboratively with ADAS to carry out the restoration work. As the restoration progressed, observations were fed into the review process to improve the original approved restoration scheme. The restoration plan evolved as techniques improved.
The original plan had been to retain and store the top 20cm of topsoil for future use as a seed source for restoration. However, it was found that seeds below 50cm of the surface of the stockpile soon died. Instead, in later phases, where soils was stripped and placed directly onto restoration areas the regeneration of target vegetation, including heather, was successful. Where topsoil storage was unavoidable, it was used as a soil resource, and alternative seed sources were necessary.
Land-forming
One aim of the restoration was to create an undulating landform containing many small microhabitats. In order to retain this, low ground pressure equipment was used for cultivating the land-formed areas.
Vegetation establishment
The soil type of a given area is crucial when deciding what vegetation to establish, and what methodology to use. Soil moisture content was monitored and on some soils, drainage was necessary in order to ensure this was appropriate for a particular vegetation. Nutrient levels and the content of any existing seed bank were also monitored. In some cases, it was necessary to manage these in order to achieve the final vegetation community required.
Peat was found to dry out very quickly if left exposed, but this was prevented by immediately sowing a grass crop to protect the peat. The grass cover grew best where moderate compaction of the peat had occurred, and a small amount of fertiliser had been applied. Once heather plants were established, no further fertiliser was applied, thereby allowing soil nutrients to return to levels more suitable for the heathers.
Rabbits
proved to be particularly problematic on the site, but have been successfully excluded from specific areas using rabbit-proof fencing. There was also anecdotal evidence to suggest wind exposure may also suppress or affect the success of heather growth, as heather was found to establish better in sheltered locations.
Control of aggressive grasses and weeds
from adjacent areas was necessary. Herbicides were used on a case-by-case basis following appropriate advice to address each issue. Techniques were specific to requirements, for example either total or selective kill, spraying or weed wiping.
Grazing of young heather plants also caused problems, and it was concluded that livestock should be excluded until heather was firmly established.
In 2009 work was done to restore an area of the site which had become dominated by rushes. This area was burnt initially followed by heather seeding work. The area was then topped to manage any rush re-growth that occurred. This year, with some rush coming through again, a programme of weed wiping may be employed to manage the area.
Tree planting
with oak, birch, ash and alder - has taken place on an area at Kingswood Burn with a view to providing future habitat suitable for black grouse once the trees have been thinned.
Pragmatic approach
One of the most important decisions to come out of the Soils Working Party was that it was more appropriate to establish various habitats in suitable locations on site rather than the areas defined on the original restoration plan. This could be a pragmatic approach to take at other sites, if uncertainty over final landform or soil conditions makes defining the most suitable locations for a habitat particularly difficult.
Long-term management of the site
The area is being managed towards its final end use for a period of 10 years post-restoration. New techniques are applied where appropriate to complement or improve upon the establishment of each habitat.
In the long-term, the aim is to use local farmers to manage the site. They will carry out appropriate grazing systems once the various habitats are established. Further areas of the site have been fenced off to manage them with low intensity grazing.
Public benefits
Although only in the early stages of restoration, the site is attracting important species of birds such as Lapwing, Curlew, Redshank, Grey Partridge, Merlin and Hen Harrier. Local people enjoy these birds and their habitat using the footpaths throughout the site.