Economic use

Lime Kiln at Great TossonCop Grag Quarry © BGSRocks of the Yoredale Group have yielded a wide range of mineral products including limestone, coal, ironstone, sandstone and fireclay.

Most of the limestones have been quarried, at least on a small scale, and burnt to provide local supplies of quicklime and slaked lime for use as a soil improver. Large scale extraction of limestone within the district has been confined to the Great Limestone. Significant quarries were worked at Fourstones, Brunton, Ryal and Greenleighton. The Great Limestone is today worked on a large scale at Mootlaw Quarry; mainly as a source of crushed rock aggregate and as armour stone for coastal defence work. Metamorphosed Oxford Limestone is worked alongside Whin Sill dolerite at Barrasford Quarry and combined with the dolerite in certain aggregate mixes.

The coal seams of the Alston and Tyne Limestone formations are generally thinner and less laterally extensive than those of the Stainmore Formation and overlying Coal Measures, but coal has been mined, mainly from shallow underground workings, throughout the Yoredale Group. Output was largely for local domestic use, though significant amounts of locally produced coal were employed in iron smelting at Ridsdale and Bellingham. The (Bellingham) Plashetts Coal was extensively worked for the Duke of Northumberland’s tenants from at least the 18th century, from bell pits near its outcrop on Plashetts Moor. The Thirlwall Coal was worked near Thirlwall Castle, and on a rather more extensive scale at Robin Rock Drift (Ventners Hall Colliery) until the late 20th century. An opencast mine working a seam probably equivalent to the Thirlwall Coal, was operated at Brieredge near Bellingham between 1984 and 1988. Thin coal seams within the Alston Formation beneath the Three Yard and Four Fathom limestones were mined on a small scale in the vicinity of Housteads and Cawfields. Commercial interest centred on the Little Limestone seam, which was mined extensively in the south of the district until the closure of Blenkinsopp Colliery in 2004. The seam was worked opencast at Melkridge from 1975 to 1977. A thin coal above the Oakwood Limestone was once worked from a small colliery in Haltwhistle Burn.

Although many mudstones in the Yoredale Group contain ironstone nodules it was only at restricted horizons that the nodules were big enough and sufficiently concentrated to warrant economicextraction. Roman iron smelted from the Redesdale clay ironstone deposits has been reported from Corbridge. Ancient bloomery sites in the Grasslees valley date from the 13th/14th century. Rows of clay-ironstone nodules (locally called “catheads”) in the Lewis Burn were collected and smelted in the nineteenth century. Ridsdale and Bellingham were thriving centres of mining in the 19th century obtaining ironstone from the Redesdale Shales, the largest nodule recovered was reported to weigh 23 kg. Clay ironstone nodules in the shales above the Three Yard Limestone were also quarried in the 19th century, in Brackies Burn, north-west of Vindolanda and on Cawfields Common. Ironstone was also worked near Brinkburn.

Many of the sandstones have been exploited as building stones from an early date, current working quarries include Cop Crag, within the National Park.

The mudstone and seatearth associated with some coals were worked as brick and pottery clays including at Haltwhistle, Bardon Mill and Langley in the south andPlashetts in the north.

Gilsland, in the extreme west of the district was, during the 18th and 19th centuries, a watering place and spa resort, based around the sulphurous and chalybeate (iron-rich) springs, which arise from pyritous shales in the Alston Formation rocks in the southern end of the Gilsland gorge of the River Irthing.

Extraction of the Great Limestone at Mootlaw Quarry is likely to continue. Future interest in iron ore working is extremely unlikely. Although there are reserves of coal probably suitable for further small-scale workings by both deep mining as well as by opencast methods, the thinness, variability and generally poor quality of the seams make it unlikely that any large scale working of these coals can be envisaged in the foreseeable future. The extraction of good quality building stone may be expected to continue from existing working quarries. Increased demand for, and popularity of, natural stone as a construction material and for repairs to existing stone structures may lead to interest in further working of previous deposits, or the search for new quarry sites.