Northfleet Cement Works
Cement Making at Northfleet
By Tom Burnham
Northfleet Works when built had 6 rotary kilns which were among the largest (in size) ever built. Total rated output was around 3.8 million tons a year (world's largest cement works when built) which would have needed some 600,000 to 700,000 tons a year of coal.
The chalk was moved from the quarry face to the washmills by conveyor belts. The washmills are basically large circular concrete tanks with a gantry with chains hanging from it rotating inside. Chalk and water go in, and the chalk is gradually ground down into a fine slurry. The flints help with the grinding, then fall to the bottom and are scooped out at intervals. The chalk slurry goes down to the works by pipeline, where it's mixed with clay slurry. Clay was dug at South Ockendon, Essex, made into a slurry and piped through a pipeline under the Thames (two were laid in, actually, in case one was ever blocked). The mixed chalk/clay slurry went into one end of the kilns, was gradually dried and heated up to about 1250°C by a pulverised coal flame at the other (slightly lower) end. The works was later altered with filter presses to remove some of the water in a more energy efficient way. The fired material (called clinker - rather like little grey pebbles) drops out of the hot end of the kiln, is cooled and then ground with about 5% of gypsum (to control the setting time) to make cement.
The gypsum was also delivered by rail of course, from Mountfield Sidings on the
Hastings line. I believe the fleet of gypsum hopper wagons was APCM-owned (they
certainly had Blue Circle logos) as were the bulk cement wagons (at first 100t
GLW bogie vehicles, later partially superseded by 45t 4-wheel wagons -
especially after some bogie wagons were lost in the Mottingham derailment). The
MGR coal hopper wagons were BR owned.
19th July 2007
An eastward view from Northfleet's ''up'' platform on 19th July 2007 reveals the extent of the remaining
site. The palisade fencing dates from 2003. The elevated ''domestic'' platform of Ebbsfleet can be seen in
the background. David Glasspool
19th July 2007
The loop line to the cement works was routed through an exhausted chalk pit to the south of the works,
once excavated by the previous Bevan Works operation. In the background, to the right, can be seen
the land re-used for sidings for the Channel Tunnel Rail Link. Much of the surrounding area was cleared
of vegetation for this, but plant life has since grown back. The electronic substation mentioned in the
main text can clearly be seen on the left. Remaining track work from the loop line can just be seen
emerging in the middle distance in this 19th July 2007 view, but this will become clearer in the next
picture. David Glasspool
19th July 2007
A southward view across the chalk pit on 19th July 2007 reveals Church Path Pit CTRL sidings, the Ebbsfleet
connection with the ''down'' track of the North Kent Line and, in the foreground, redundant points of the former
cement works loop line. David Glasspool
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