Clinker manufacture operational: 1963 to date
Approximate clinker production to 2015: 38 million tonnes (10th)
Raw Materials from the lower Carboniferous Limestone (Lower Limestone Formation: 322-331 Ma), in quarries at:
The deposit has the following sequence (top to bottom):
Also known as Oxwellmains Works. The limestone here was long known as the best in lowland Scotland, and the Oxwell Mains lime works, supplying the Scottish steel industry, was situated on the plant site, using drift mining. Until acquisition by Blue Circle, it was owned by Coltness . The two limestone seams, with substantial overburden and interburden, are extracted by a unique narrow slot mining technique that continuously restores the land as the face moves forward. As a result, the earlier quarry is already under agriculture. The limestone contains a few thin coal seams which benefit the fuel efficiency of the plant, giving it in the early days the lowest fuel consumption of any plant.
A Lepol plant was installed, although a suspension preheater system was feasible, because technology could be cheaply transferred from the successful Cauldon plant. With the installation of the third kiln in 1966, Dunbar became Blue Circle’s largest UK plant until overtaken by Hope in 1970.
The rawmills were distant from the kilns and could not use waste heat from the kiln system for raw material drying. They were heated with fuel oil, with typical heat usage 0.20 MJ/kg.
Please contact me with any relevant information or corrections. I am particularly interested in firmer dates and statistics.
Note: technical information on currently operational plants is ✄withheld in the public version of the site at present.
Three rotary kilns were installed:
Sources: Jackson, pp 222, 278: Pugh, pp 144-146, 156-161: “The New Dunbar Cement Works”, Cement and Lime Manufacture, 37, January 1964, pp 1-18: Dunbar Works, Blue Circle Publicity Department, 1967: M. Scrutton, M. G. Jones. and J. P. Elvins, “Dunbar Cement Works quarry, East Lothian: 45 years on” in Proceedings of the 14th Extractive Industry Geology Conference, EIG Conferences, 2008, pp 12-20.
© Dylan Moore 2011: commenced 07/08/2011: last edit 14/12/2016.
Approximate capacity: tonnes per year: ✄
Picture: ©Lisa Jarvis 2007, and licensed for reuse under this Creative Commons Licence. See this and related images on Geograph. This shows the plant in 2007, viewed from the southwest. The separate stack through which the kiln gases leave the system is that of the SO2 scrubber. Because wet scrubbing is used, the plume carries a large amount of water vapour.
Picture: ©Walter Baxter 2010, and licensed for reuse under this Creative Commons Licence. See this and related images on Geograph. This shows the plant in 2010, viewed from the west.
Dunbar in 1976. Picture: ©NERC 1976: British Geological Survey Cat. No. P001495. This shows the view from the southeast of the Lepol plant prior to conversion to precalciner process. The nearer kiln building is that of kiln 3. The Bass Rock in the Firth of Forth can be seen on the horizon.