Economic use
Bellcrag Flow, Border MireThe extensive spreads of glaciofluvial and Holocene age alluvial sands and gravels in the district have encouraged a fairly high level of extraction in the past. The alluvial terraces of the Tyne are regular in depth and are predominantly composed of graded gravels, the finer material having been washed out. These terrace gravels tend to be primarily composed of Carboniferous sandstones with some lower Palaeozoic greywackes, with limestone and some igneous rocks. Extraction has taken place all along the Tyne from Gilsland in the west, to Crawcrook in the east, with numerous small-scale pits being worked predominantly in the alluvial terrace material. Possibly the most extensive working of the glaciofluvial material has been at Prudhoe Gravel Works.
The Milfield Fan is predominantly composed of sands and graded gravels. There have been extensive sand and gravel workings at Woodbridge Farm Quarry at Milfield since the 1960s, and this quarry is still in operation. The Lanton Quarry is set to continue working after Woodbridge Farm Quarry has closed, and in 2000 had estimated reserves of 1.8 million tonnes. Further to the south Branton and Low Hedgeley quarries have also produced significant yields of sand and gravel, though their operations are winding down, with the Branton site now having been largely restored to artificial lakes. At Thrunton the brick clay quarry continues to extract laminated glacial lake clay.
Traditionally, peat has been drained and cut for fuel in the district, but in recent years it has been extracted on a commercial basis and sold for horticultural use. Peat is currently extracted at two sites in Northumberland on the north-eastern margin of the district, Kemping Moss near Lowick and Greymare Farm near Belford. Extraction at a third site, Bell Crag Flow, within the National Park, has ceased and the site is being restored by blocking drainage ditches and removing self-seeded conifers. There is now a presumption against opening new peat extraction sites as the peat habitats are now recognised as being important for biodiversity, carbon storage and water retention.
Even though the Tyne valley has extensive sand and gravel deposits, it is clear from the scale of historical extraction that they have limited future potential. The deposits occur in narrow units (less than 500 metres lateral width), and are less than 10 metres thick in most places. Other UK sources of such material are more economically viable. By far the largest potential future source of sand and gravel resources remains the Milfield Fan. However the extent to which it has already been excavated may prevent further development due to fears over the complete loss of the feature. The Milfield Plain may prove to support thick sequences of glaciolacustrine (related to the glacial lake) muds and sands, of use to brick clay and sand resource industries. However, this area of high quality land is currently extensively farmed, and is beneath the eastern flank of The Cheviot, close to the National Park borders, and thus any proposed extraction may meet with local difficulties. The proximity of sites to the National Park renders the area sensitive to further large-scale resource extraction and stringent planning and environmental conditions would have to be met in any proposals for future working of the sand and gravel deposits.
