Clinker manufacture operational: 1877-1971
Approximate total clinker production: 22 million tonnes (19th)
On the 1872 map, there was a quarry on the site, with a tramway leading to what became “Johnson’s Wharf”, for supplying chalk ballast. It was claimed by Johnson to be one of the oldest chalk ballast quarries on the Thames, and it had previously supplied I. C. Johnson’s plant at Gateshead. Johnson bought the freehold around 1875, and had a plant with 15 Johnson kilns in operation by 1877 (rated output 350 t/week). The number of chamber kilns rose to 54 before rotary kilns were installed. The rough sequence of expansion was as follows:
All these had (according to Johnson) heat consumption ~10.6 MJ/kg. This oft-quoted figure is undoubtedly an under-estimate, referring only to “flat-out” production. Since capacity utilization was typically 60-70%, normal heat consumption was probably much nearer the 14 MJ/kg typical of chamber kilns.
The company was part of the APCM amalgamation in 1900, but dropped out, as did West Kent and Weekes. The departure of Johnson’s caused particularly bad feeling, since the company was a major player, and its directors had been much involved in the project. The company tried hard to repair relations with APCM, and after the BPCM takeover, it played a major part in the new company. Because of its significant chalk land holdings, the plant remained an important part of Blue Circle’s Thames-side operation. Kilns A4-A7 demonstrated a commitment to aggressive expansion, and A6 and A7 were Britain’s largest kilns until overtaken by West Thurrock A6 in 1934, providing Vickers Armstrong with a successful design that was subsequently installed at many other locations. The addition of kilns 6 and 7 also made the plant Britain's largest from 1930 (overtaking Bevans) to 1933 (after which it was overtaken by West Thurrock). The plant became too cramped for further expansion after this. Johnson’s 91 m brick stack, constructed originally for the chamber kilns in 1877, remained in use until closure. The plant made sulfate resisting clinker alongside ordinary clinker from the late 1940s to 1971. The plant was the first on Thames-side (1933) to fit electrostatic precipitators.
Initially relying solely on its wharf for shipping, a rail link was established from the 1900s, but water transport remained important for despatch of product. After closure, the site was re-developed. Johnson’s Wharf, originally used for chalk export, is still in use, ironically for intake of aggregates for a Lafarge ready-mix plant. The plant site is largely under a housing estate. The original quarry is now a small park, and the site of the old stack, once the tallest in southern England, is preserved on a small mound. The main chalk quarry became the Western Quarry for Northfleet, and is now occupied by the Bluewater Retail Park.
Washmills were used, located at various places around the plant site, fed with chalk brought by rail from the quarry and clay by rail from the wharf. While the Bean clayfield was in operation, clay was washmilled there, and pumped to the plant. The chamber kiln plant had two washmills (? 15’ - ?30 kW each) in series with a set of six flat stones (20-25 kW each). In the final (late 1920s) plant there were two 30’ (168 kW) washmills. Larger grit was removed from the washmill product by eight vibrating screens, then the fine slurry was distributed between four 261 kW tube mills. The screen oversize was passed to two 22 kW screening mills, with the fine product returning to the main washmills. Material rejected by the washmills and screening mills entered an elaborate flint handling system.
Seven rotary kilns were installed:
Supplier: Ernest Newell
Fuel: Coal 1913-1960: Oil 1960-1966
Cooler profile: 0×2083: 1067×2565: 5029×2565: 6401×1930: 25146×1930: Tyres at 3810, 18796.
Rotation (viewed from firing end): clockwise.
Fuel: Coal 1928-1960, 1968-1971: Oil 1960-1968
Kiln profile: as A6, with modifications at slightly different dates.
Typical Output: 1928-1930 433 t/d: 1930-1950 493 t/d: 1950-1960 497 t/d: 1960-1968 494 t/d: 1968-1971 449 t/d
Sources: Eve, p 13: Francis, p 154: Jackson, pp 232, 283: Pugh, pp 264-265: Building News and Engineering Journal, 2/7/1880 pp 5-7: The Engineer, XCIII, February 7, 1902, pp 130-133: ibid, CV, February 28, 1908, pp 211-213, 220: “Johnson’s Cement Works, Greenhithe”, Cement and Cement Manufacture, 2, 1929, pp 97-107, 161-170.
© Dylan Moore 2011: commenced 12/03/2011: last edit 18/12/2016.
This is a composite map containing details from different eras that may not have co-existed.Approximate capacity: tonnes per year
Kilns 1-3 viewed from the top of the back-end chamber, around the time of commissioning in 1907. A typical "second-generation" kiln installation. The concentric coolers can be seen below the kilns.Britain from Above features some of the oldest and most valuable images of the Aerofilms Collection, a unique and important archive of aerial photographs. You can download images, share memories, and add information. By the end of the project in 2014, 95,000 images taken between 1919 and 1953 will be available online.
This was taken in September 1924 and shows the plant from the east in a period when the first five are present. Kilns 4 & 5 are in the open, with a long duct connecting them to the tall 1874 stack. Kilns 1-3 are still in place (near the bottom edge) although apparently not running. The rawmills and finish mills are still in their original location. The old chamber kilns are still relatively intact, although long disused. In the right background is the disused Artillery plant with a tall stack. Zoom in on the plant in High Definition. This was taken on 27/2/1939 and shows the plant from the southeast. Kilns 6 & 7 are running. Kilns 4 & 5 are in the open, to the right of the kiln house. To the left of the kiln house the remains of the main chamber kiln bank can still be seen. In front of the main stack are the electrostatic precipitators that had been retro-fitted on the kilns in 1933. The new washmill plant is in the foreground. To the right of the washmill sidings are tanks holding clay slurry. By 1939, clay slurry was being delivered by barge from Cliffe. The centre is occupied by the new finish mills and cement silos built over the site of kilns 1-3. In the right foreground is the bank of shaft limekilns that continued in use into the 1960s. In the right background is the Kent plant. Zoom in on the plant in High Definition.