Cement Kilns

Dunbar

Location:

  • Grid reference: NT7066276317
  • x=370662
  • y=676317
  • 55°58'44"N; 2°28'13"W
  • Civil Parish: Dunbar, East Lothian

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:

  • 1963-1982: South Quarry at 371300,675700
  • 1982-2006: Northwest Quarry at 370400,677000
  • 2006 to date: Northeast Quarry at 371500,676800

The deposit has the following sequence (top to bottom):

  • 2 to 20 m overburden, consisting of drift, magnesian limestone, sandstones and shales
  • 1.2 m shale – used
  • 5.2 m upper limestone – used
  • ~10 m of interburden, consisting of magnesian limestone, sandstones and shales
  • 7.2 m lower limestone – used
Additionally some sand – either bought in or interburden – is added.

Ownership:

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.

The plant was changed to precalciner operation in 1986, as with Cauldon, mainly in order to simplify the plant and allow operation with a smaller workforce.

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.

Rawmills

  • 1963-1986: One 1350 kW Aerofall mill for coarse grinding and one Head Wrightson 900 kW ball mill for separator rejects regrind. A second regrind mill was installed in 1966.
  • 1986 to date ✄.

Three rotary kilns were installed:

Kiln A1

Supplier: Polysius
Operated: 01/04/1963-1986
Process: Semi-dry: Lepol 20.9×3.91 m grate
Location: Hot end 370630,676340: Cold end 370691,676324: entirely enclosed
Dimensions: Metric 63.00 × 3.793
Rotation (viewed from firing end): anti-clockwise
Slope: ?
Speed: ?
Drive: 82 kW
Kiln profile: 0×3340: 900×3340: 1800×3793: 62000×3793: 62500×3023: 63000×3023: Tyres at 4400, 22400, 34400, 55400.
Cooler: Fuller 744H grate
Fuel: Coal
Coal mill: direct: MPS90 roller mill
Typical Output: 1963-1969 684 t/d: 1970-1980 774 t/d: 1981-1986 684 t/d
Typical Heat Consumption: 1963-1969 3.38 MJ/kg: 1970-1980 3.19 MJ/kg: 1981-1986 3.29 MJ/kg


Kiln A2

Operated: 29/04/1963-1986
Location: Hot end 370626,676327: Cold end 370687,676311: entirely enclosed
Typical Output: 1963-1969 675 t/d: 1970-1980 761 t/d: 1981-1986 665 t/d
Typical Heat Consumption: 1963-1969 3.38 MJ/kg: 1970-1980 3.20 MJ/kg: 1981-1986 3.31 MJ/kg
Identical in all other respects to A1


Kiln A3

Supplier: Polysius
Operated: 20/09/1966 to 1984, 1986 to date
Process: 1966-1984 Semi-dry: Lepol 27.7×3.91 m grate: 1986 to date air-separate precalciner: details✄
Location: Hot end 370622,676310: Cold end 370680,676295: entirely enclosed
Dimensions: Metric 60.00 × 3.916BC / 4.351D
Rotation (viewed from firing end): anti-clockwise
Slope: 3.5% (2.006°)
Speed: 1.1 rpm: from 1986 increased to ✄
Drive: 134 kW: from 1986 increased to ✄
Kiln profile: 0×3519: 911×3519: 1811×3916: 49036×3916: 52311×4351: 59011×4351: 59620×3640: 60000×3640: Tyres at 4737, 27237, 47737: Turning gear 44737.
Cooler: Fuller 850H grate: from 1986 grate: details ✄
Fuel: Coal, from 1986 ✄.
Coal mill: direct: MPS100 roller mill: from 1986 ✄
Typical Output: 1966-1970 836 t/d: 1971-1979 1048 t/d: 1980-1984 867 t/d: from 1986 ✄
Typical Heat Consumption: 1966-1970 3.37 MJ/kg: 1971-1979 3.19 MJ/kg: 1980-1984 3.26 MJ/kg: from 1986 ✄



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.

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Old Maps

Detail plan of the plant in preparation.

Approximate capacity: tonnes per year: ✄


Dunbar 2007
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.


Dunbar 2010
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 1976
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.