Bulk minerals resources, Southern Uplands

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Stone, P, McMillan, A A, Floyd, J D, Barnes, R P, and Phillips, E R. 2012. British regional geology: South of Scotland. Fourth edition. Keyworth, Nottingham: British Geological Survey.

Introduction[edit]

Quarry at Sanquhar brickworks, reported as being near the railway station, early 1920s. In the upper part of the working face a dark layer of peat is present within the till deposit. P001449.

Sand, gravel and crushed rock are extracted for use as construction materials, as a concrete aggregate, and for roadstone. The working of limestone for the production of agricultural lime has been of historical importance locally.

Sand and gravel[edit]

Sand and gravel are principally derived from glaciofluvial outwash deposits in the major valleys, including those of the rivers Nith, Annan and Tweed. The available resources at any one locality are usually restricted, and the small-scale operations that they sustain supply mainly local markets, a distribution pattern encouraged by the high cost of transport in relation to the relatively low value of the materials. The most extensive operations work the deposits around Dumfries, Lochmaben, and to the south of Stranraer. Most of the gravels are compositionally dominated by the local wacke-sandstone, which is a lithology that can give rise to shrinkage in concrete.

Crushed rock aggregate[edit]

For crushed rock, both the ubiquitous Lower Palaeozoic wacke-type sandstones as well as a range of igneous rocks have been worked at a number of localities. The igneous rocks range from the upper Silurian to Lower Devonian granites of the south-west to the Carboniferous basaltic lavas and microgabbro intrusions of the Border country in the south and south-east of the region. The more important of the quarries active in the late 20th and early 21st centuries are described briefly below.

The largest wacke sandstone quarry in the region is at Morrinton (NX 870 815), some 12 km north-west of Dumfries. Here, sandstone of the Gala Group is crushed for roadstone and concrete aggregate, with an adjacent block-making facility. Another large quarry in the south west is at Barlockhart (NX 213 565) near Glenluce, where Gala Group sandstone has been baked and hornfelsed in proximity to the Glenluce diorite intrusion. A quarry at Bore-land Fell (NX 348 594) near Kirkcowan has produced crushed wacke-sandstone from the Mindork Formation, whilst another at Coatsgate (NT 064 053), near Moffat, works wackesandstone of the Queensberry Formation, both units within the Gala Group. The Queensberry Formation sandstone was also worked nearby at Garpol Linn (NT 069 030) where a large temporary quarry was opened during construction of the M74 motorway. To the north-west of Langholm, Hawick Group (Carghidown Formation) wacke sandstone was formerly worked from a quarry at Peden’s View (NY 345 862). In the east of the Southern Uplands, a series of quarries in Gala Group wacke sandstone along the A7 road north of Galashiels, including Hazelbank (NT 425 505), Bower (NT 429 501) and Craigend (NT 444 461), mostly ceased operation during the last half of the 20th century, though some work at Hazelbank continued until the beginning of the 21st century.

Crushed granite is produced at Craignair (NX 819 608), near Dalbeattie, an area which was once renowned for its output of granite blocks used in substantial engineering projects (see below). Tongland Quarry (NX 698 544) near Kirkcudbright produces aggregate from both sheet-like bodies of intrusive diorite and the host, contact-metamorphosed wacke sandstone. Kirkmabreck Quarry (NX 479 565), near Creetown, is an intermittent producer of crushed granite but is used mostly to extract large blocks of granite from time to time, as and when required.

The quarry at Tormitchell (NX 234 944), about 6 km south-east of Girvan, is unusual in the south of Scotland in working a limestone for aggregate (the Stinchar Limestone of the Ordovician Barr Group) as well as the adjacent wacke sandstone units. Some Carboniferous limestone produced from quarries near Canonbie has also been used locally for roadstone, though these operations were primarily for the production of agricultural lime (see below).

Near Duns, in the east of the region, Borthwick Quarry (NT 770 543) works a large, Carboniferous intrusion of basalt on an intermittent basis. The Carboniferous Kershopefoot Basalt has been worked for roadstone to the north-east of Langholm at Kersehope Quarry, adjacent to Kersehope Bridge (NY 500 834).

Limestone[edit]

Wherever Carboniferous limestones are exposed there have been numerous small workings and associated kilns for the production of agricultural lime. Many of these were 18th or 19th century operations, and during the early 20th century production became centred on larger quarries. In the Oldhamstocks Basin succession, to the south of Dunbar, many of the Visean limestones within the Strathclyde and Clackmannan groups have been worked locally and on a small scale; well-preserved limekilns survive in places, for example at Catcraig (NT 717 773), adjacent to the old quarries. More recently, large-scale quarrying for cement production has been developed at sites around Oxwell Mains (NT 707 764), collectively known as Dunbar Quarry and situated about 2–3 km south-east of the town. The Hurlet and Blackhall limestones of the Lower Limestone Formation (Clackmannan Group) are utilised there, together with some of the associated mudstones. In south-west Scotland, a similar 18th and 19th century history of small-scale quarrying pertains in the Canonbie area, with more recent operations most notable at Harelawhill (NY 426 789), where Brigantian limestones of the Alston Formation (Yoredale Group) were extracted by both opencast quarrying and through underground workings (P917567) until about 1970. In the Thornhill outlier of Permo-Carboniferous strata, the Visean (upper Asbian to Brigantian) Closeburn Limestone Formation was of sufficient thickness and quality to have been mined at several sites near Closeburn and burned for agricultural lime in the late 18th century; well-preserved limekilns remain near the Croalchapel quarry site (NX 911 915). Underground, stoop-and-room excavation of the Closeburn Limestone was employed farther west at Barjang (NX 882 902), albeit on a limited scale.

Brickmaking[edit]

There has been much small-scale exploitation of localised lacustrine, alluvial or glacigenic clay deposits for the manufacture of bricks and tiles. Such operations were largely resticted to the 18th and 19th century, but some continued until more recent times. Typical was the Tarrasfoot Tile Works near Langholm which operated from the mid 18th to the mid 20th century, initially producing bricks but in later years turning out drainage pipes for local agricultural use.

In common with the practice in many other coal mining districts, bricks were produced from mudstones in the Coal Measures succession in the Sanquhar Coalfield, especially at Sanquhar and Kirkconnel. Near the railway station in Sanquhar, the Buccleuch Terra Cotta Works produced high quality terracotta bricks and tiles of an attractive red hue, which can still be seen incorporated into many of the local buildings. The mudstone workings are shown in P001449 as they appeared in about 1920.


Bibliography[edit]

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