Stockton

Stockton Logo Nelson's Cock Brand.

Location:

  • Grid reference: SP44196480
  • x=444190
  • y=264800
  • 52°16'46"N; 1°21'8"W
  • Civil Parish: Leamington Hastings, Warwickshire: the lias quarry and the raw material preparation plant were in Stockton parish

Clinker manufacture operational: 1872 to 5/1945

Approximate clinker production: 1.83 million tonnes

Raw materials:

  • Blue Lias Limestone and Clay (Rugby Limestone Member: 195-200 Ma) from quarry at 444250,264250, upgraded by rumbling. The Lias was 60% clay of around 35% CaCO3, and 40% limestone of around 78% CaCO3, and most of the clay was sidecast.
    • before ~1880 quarry at 443900,265000
    • ~1880-1900 quarry at 443900,264800
    • 1900-1945 quarry at 444400,264300
  • The Lias was of too low a grade for modern cement, and from 1919, supplementary high-grade sweetener limestone (4-11% of dry rawmix) was bought:
    • initially Great Oolite limestone (Blisworth Limestone Formation: 165-168 Ma) from Roade, Northamptonshire (475900,251520) (39 km by rail)
    • after 1934 also Inferior Oolite limestone (Lower Lincolnshire Limestone member: 168-172 Ma) from Corby, Northamptonshire (492010,289090)

Ownership:

Sometimes called Nelson’s Works. The site made lime from early times and like Southam had its own dock on the Grand Union Canal. The manufacture of “cement” dates from 1857, but as with the other Warwickshire plants, true Portland cement was not made until later: around 1872 in this case, when two small dry process bottle kilns were employed. The number of small bottle kilns was gradually increased, and a set of chamber kilns may have been added, perhaps around 1889.

A historical account of this plant is hampered by lack of data, and particularly by lack of maps. As with many rural areas, there is no map edition between the 2nd edition County Series of 1909 and the late 1960s revision. This means that no map shows the rotary kilns, and the only evidence for their location are a few poor quality aerial photographs of the 1930s. The fact (if it is a fact) that there were chamber kilns originates from a statement in a valuation document drawn up by a law firm in 1910 (Rugby Archive RS/9/1/5/6) which says “there are several old slurry drying Kilns, no longer required as such, which we understand will be converted into, and used as Clinker Stores.” The 1909 map does not depict anything that can be unambiguously identified as a chamber kiln block. The 1930s aerial photography shows an area where clinker is being stacked, with little indication that it might once have accommodated chamber kilns, but if it did, then a rectangle 98’ × 80’ can be identified, and, as it happens, there is a tall brick stack at one corner. This, depending on orientation, could contain six 22 tonne or four 30 tonne kilns. This information could be regarded as tenuous enough to ignore, were it not for the fact that the maps show the bottle kilns to be very small – the twenty-three amounting to only 302 t/week capacity. With the three Schneider kilns making 240 t/week, some 160 t/week extra capacity is needed to make the 700 quoted by Davis. (Davis is generally very reliable, using his own objective expert assessments of the plants rather than “declared” capacities.) I therefore go for the 6×22 tonne arrangement. Further circumstantial justification is the fact that wet process rotary kilns were chosen. All the Warwickshire manufacturers were watching each other closely at this time, and collaborating to a significant extent. Both Rugby and Harbury had chamber kilns and chose the wet process. Southam had dry process bottle kilns and chose the dry process. Previous experience of making slurry was evidently decisive, and without chamber kilns, Stockton would have had no need to make slurry.

Around 1902, three of the later bottle kilns were converted into Schneider kilns. By 1907 there were 8 lime kilns and 23 cement bottle kilns (305 t/week), six chamber kilns (135 t/week) and three Schneider kilns (240 t/week), totalling 680 t/week, corresponding to Davis’ estimate of 700 t/week. The Schneider kilns were converted to forced-draught (together 450 t/week) in 1908. These used dry-ground briquetted rawmix. The use of static kilns ceased in 1913. New continuous lime kilns were installed at the same time as the rotary kilns, and the plant continued to make a significant amount of Lias lime.

The plant did not expand up to the depression, and Rugby took a share in the near-bankrupt company in 1937. Following complete takeover in 1945, it became clear that there was no point in keeping it as a separate unit alongside the newly modernised Southam, and production ceased immediately, with the plant continuing to function as a depot until it closed in 1949. In addition to the canal, the plant also had a railway connection through the L&NWR Weedon-Leamington branch from 1895. The plant site remained derelict for many years, and was finally cleared of structures in 1968. The canal spur was filled in and the site has remained waste land, with foundations still visible. The quarries are partially back-filled, but mainly flooded.

Although this was the most important Warwickshire plant at the start of the twentieth century, information is hard to come by, and this account is far from satisfactory. Please contact me with any relevant information or corrections. I am particularly interested in firmer dates and statistics, pictures and plans.

Rawmills

Originally Collis and flat stone mills were used, grinding stone brought from the quarry by tramway. By 1905, they had 3 tube mills (size unknown) for wet grinding. In 1919, a wet "combination" tube mill was installed at the quarry, and the Lias was pumped to the plant as a slurry. At the plant, a second combination mill ground the slurry with added bought-in sweetener limestone.

Two rotary kilns were installed:

Kiln A1

Supplier: Edgar Allen
Operated: 6/1910-5/1945
Process: Wet
Location: hot end 444199,264766: cold end 444187,264725: totally enclosed
Dimensions: 140’0” × 8’0”B / 7’0”CD (metric 42.67 × 2.438 / 2.134)
Rotation (viewed from firing end): anticlockwise
Slope: ?
Speed: ?
Drive: ?
Kiln profile: 0×2134: 2134×2134: 3658×2438: 7010×2438: 10668×2134: 42672×2134: tyres at 1524, 11887, 24308, 37338: turning gear at 24841.
Cooler: rotary 50’0”× 5'0"/4’0” (metric 15.24 × 1.524/1.219) beneath kiln
Cooler profile: 0×1219: 1219×1524: 4572×1524: 5486×1219: 15240×1219: tyres at 2438, 11887: turning gear at 12192.
Fuel: Coal
Coal mill: indirect: common rotary drier followed by combination tube mill
Typical Output: 1910-1921 54 t/d: 1922-1933 60 t/d: 1934-1945 75 t/d
Typical Heat Consumption: 1910-1933 9.48 MJ/kg: 1934-1945 9.03 MJ/kg


Kiln A2

Operated: 1913-5/1945
Location: hot end 444204,264765: cold end 444192,264724: totally enclosed
Rotation (viewed from firing end): clockwise
Identical in all other respects to A1



Sources: Cook, p 115: Francis, pp 215-216: Jackson, pp 288, 299

The Warwickshire County Record Office holds sales ledgers from Charles Nelson & Co's plant at Stockton (temporary catalogue numbers RS 9/5/1-5). I present the data here because it represents an exceptionally long (over 50 years) time series of uniformly-gathered data, and because it refers to the idiosyncratic history of the Warwickshire industry. In Warwickshire, the Blue Lias district produced "engineering-grade" hydraulic limes from the 18th century, and these became popular throughout Britain when the building of canals allowed them to be distributed nationwide. When Portland cement began to be produced from the 1840s onwards, Blue Lias Lime was one of the established products with which it had to compete, and the reliability of this lime ensured that it remained in favour for certain applications well into the 20th century. Its production continued at the Warwickshire plants until WWII.

The Stockton plant was established on a site previously worked for lime in 1844. Portland cement made with a ground rawmix commenced production in 1872, and by 1886 its capacity was 15000 t/year of Portland cement and 25500 t/year of lime - about 63% lime. The lime was marketed in three forms: lump lime, ground lime and Selenitic lime. The vast majority (80-90%) was sold as ground lime, which is the familiar Blue Lias hydraulic lime, made by grinding the lump product without any slaking. Lump lime was probably made from stone from known high-carbonate floors. Selenitic lime was made by adding 5% gypsum at the grinding stage as a retarder, and was used in mortars. By the start of the following records in 1897, the relative position of lime and cement had reversed, with lime down to around 40% of tonnage.

YearOwn Product Sold tonnesPurchased Materials Resold tonnesTotal Sales tonnes
Lump LimeGround LimeSelenitic LimeOPCRHPCLump LimeGround LimePlasterCementLump LimeGround LimeSelenitic LimePlasterCement
18974741404280015574020664484347730425401852680034722878
1898953148071062209520252648185124476347919625106251225428
1899911137121118205070197840985005120288917810111850025627
1900465119531471204800189357055578152235817658147155728632
1901802130051182209550110349556826883190517960118268227838
190287812138158820533079428635636455167215001158856326988
1903170614241103422717068428574367686239017098103443630403
1904171115582110622397035724573686755206818039110636829152
190531989661943238800271950395471234691061194339528592
19062314115668322774104361275419466827501284183241932409
1907281997119312370307016642241032889987793142227806
1908256576297102001509046237132072655809171037123222
190919198461792166640140023024302059846179223019094
191031139507651251570210061124193323950765161127576
19112040735354632171032212769730402362748054669735211
19121158710844041042015710123125451315720944023143587
191377455466344047705802184433832554663421844910
19141580420716939679081014253201661420716914244999
1915583263614531530012121125251704263814511236781
19163914161152933505409819889314161159831323
19176391357251980101991188573932579127083
19186710058123776015893957821013819324733
191914798462358203562062059498044620625641
1920716455726703053026030896016455726029792
192136016102732319408811241891448162127324124085
192233421611413364605611491142390216214114934788
19233146675883677203415112202634866908811238798
1924246344648306470390152176028534464815232407
19254293563973678504815148125047735789714838035
192628326106732894013911203108042226216720333974
1927257269831355880616021427287326983121435860
192823825282837634002525642323825532825638057
192918525373931954064030547524925373930532429
1930181381974335940761044526725738297444533861
1931442292089323530221266928446429328966932637
193220223167233312034070817623623167270833488
1933226344078349570211249223424734527849235191
1934336287884354740710791194072878847935593
19353443005131377270681680219412300613168037946
19367973720125477290125440818440922416012581848169
1937860380318950645115890326465289950412918946552092
1938216369380489621739306817117124637618017150872
193934321211456166196297448349543328611448358623
1940832566194640824555884066708826541940649533
1941101440104148021501096494472015361049443677
19420125103537926249153414183091404041439833
1943071603160319200268354450984035433568
1944077702980515590030900777030931364
194504970235091460022125182520718025133221
19460193013711300538313352900731031336791
1947000000723298370250723029837025
1948000000572213278170572021327817
194900000016062696701600626967

It is noticeable that, particularly in the earlier period, a large proportion of the lime and cement sold was not made by Nelsons. The majority of these materials were sold at remote sales points, particularly London, and were packed under the Cock logo by other producers - mainly the other Warwickshire producers.

stockton sales
stockton lime

The total tonnage produced on site varied remarkably little during the period, and never rose very much above the 40,000 tonnes capacity in 1886. However, the amount of lime in the mix consistently fell. It is noticeable that lime production was set aside during both World Wars. Other Blue Lias Lime producers ceased manufacture earlier: Rugby in 1932, Barrow and Southam in 1935, Barnstone in 1938, Aberthaw and Harbury in 1939.

Notes

Note 1.