REPORT
BY SARAH URQUHART OF HASLINGFIELD ACTION GROUP (H.A.G.) OF VISIT TO BARRINGTON
CEMENT PLANT AND QUARRY ON 19.12.2005.
Those attending were Diana Bird, Richard Pleasants, Primrose Taylor,
Shane Thornton and Sarah Urquhart. We were taken around by John Drayton, Quarry
Manager and Keith Marsay, Quality Manager.
This report is our interpretation of the information we were given, and
applies to the Barrington Plant in particular and not to Cemex as a whole.
The first draft of this report was discussed with Mike Scott, Measurement
and Control Engineer, and long time member of the Local Barrington Quarry
Liaison Group. Primrose inserted
some paragraphs on visual impact.
·
Cemex have permission to quarry a strip at West end of site, so clearing
woodland at Balk Plantation currently.
·
Archaeologists are doing a pre-development survey and are digging
trenches in areas to be quarried over next 25 years, and also in the route of
the proposed new roadway. They will report on any interesting discoveries (an
Iron Age farmstead?) before they are destroyed
·
25 yrs of quarrying will take Cemex as far as the Whole Way/Drift.
There is a further 15 yrs of quarrying potential beyond the drift to
Orwell, north of the path of the new roadway.
There
are several layers to the quarry –
1.
“overburden” – 8m thick – deposited in last Ice Age.
2.
Chalk
3.
Totternhoe Limestone
4.
Marl Clay
5.
Blue Clay
6.
Green sand – contains fossils – eg.
shark and crocodile teeth, ammonites, mammoth tooth, sea urchins,
icthyosaur.
7.
They excavate to 13 meters above sea level, as the clay below is
unsuitable for their use.
·
There was one digger in the plant during the visit and 2 Volvo dumper
trucks taking clay from the quarry. Each
digger weighs 125 tonnes. The
bucket can carry 45 tonnes. In the
new plant there will be 2-3 diggers.
·
There is currently a landfill site in the quarry for cement kiln dust
(CKD). This is lined with boulder
clay to prevent permeation of the alkalinity into the water table/surrounding
soil/rock. Boulder clay is
apparently virtually impermeable.
·
This process is essentially putting back what they
have removed from the ground during the quarrying process, but in a finer form.
As the clay is impermeable there is very little water table movement.
·
March 2005 – railway within the quarry itself closed, more
economically viable to use dumper trucks now.
It
is currently proposed that the base of the Pre-Heater tower be at 32 meters
above sea level. It is then a
further 40 meters to the top of the hill (72m asl) so the present plan of a
Pre-Heater tower of 122 meters would protrude above the the top of the hill by
82 meters.
It may be feasible to sink the pre-heater tower
further into the ground, meaning that less of the tower will protrude above the
hill. It is understood however that
this would cost Cemex more.
Another option may be to split the pre-heater tower
(but not the chimney, see below) into 2 shorter sections, meaning the structures
would not make such an unsightly visual impact, although they would still
protrude by 21 meters if foundations were at 32 meters, (but potential for them
to be completely concealed if foundations excavated to sea level.)
There would still be a need for a tall chimney to carry the waste gases
out. Suggestion to speak to
Mr Monty Goding, Combustion Engineer, and member of the liaison committee to
discuss this in more detail.
Rest
of Plant
John Drayton photocopied for us the large scale
drawing of the proposed new plant. There
are many factory buildings of which the Silos are the most visually intrusive.
The Clinker Silo needs a particular volume to be efficient, but the other
silos are enormous for economic convenience rather than as a requirement of the
design and could be smaller. Monty
Goding should be consulted on the feasibility of there being more units of lower
height.
The proposed plant has been angled in such a way that
a large section of the hill between the existing quarry and the Haslingfield
road would be removed. This seems
unfortunate as the hill currently acts as a very efficient shield.
Whatever Cemex build at low level within the excavated area of the
present quarry is very well hidden by the curve of the hill and the mature
woodland. Pressure should be put on
Cemex to site their new plant so that the current topography acts as a shield
from as many viewpoints as possible, and they should be prevented from quarrying
out this protective flanking.
·
Cemex say that the new road will be cut into the hill in places to try
to minimize visual impact and noise. We
should ask for the whole of the hillside road to be deeply culverted, and also
object if they plan street lights along this road, as these would be unsightly
and add light pollution.
·
The new road will be on a level to the North of Barrington (the current
farm road from the big corner by the Drift).
There are plans to construct a 3m hill like screen in front of this to
minimise noise and visual impact. As
well as this bund we should ask for a plantation of trees in the field to the
south of the road.
There will probably be a roundabout where the speed
camera is currently located on the A603 to allow cement lorries access onto the
road more safely.
Railway
A fuel train runs on average twice a week now, but as
the track needs upgrading only 5 trucks can be mobilized at once.
Cemex plan to improve the track so that a mainline locomotive can bring
in a full train. They anticipate adding one train of cement each 24 hours (in
both directions?). Each train is
equivalent to 66 lorry movements. At
present 75% of their current customer base have to be serviced by road, as only
25% have a railhead, but in future there will be train wagons that lift easily
onto a lorry making rail delivery more flexible.
There is likely to be pressure on Cemex to put as much transport as
possible onto rail rather than road, so we must assume the railway usage will
increase over time.
·
From the plant which runs 24 hours
Quarrying
at present uses a front loading shovel digger or 360 Bacco.
In the new plant, this Bacco is likely to be larger.
At present, 30 and 40 tonne dumper trucks are used to carry the chalk and
clay out of the quarry to the plant. In
the new quarry the chalk and clay will be put into a crusher and then a conveyer
system to carry it to the new plant.
·
There are 492 proposed lorry movements per day at the new plant.
Each lorry has a capacity of 28-30 tonnes.
(Need to clarify exactly what a lorry movement is, we
believe it is an entry or an exit from the plant, not a round trip).
These lorry movements apply to the business of cement
making only, so deliveries, eg of climafuel (see below) would be in addition,
and could be a considerable number.
1926
– there were 3 kilns, removed in 1994
2005
– now one kiln.
See
“Cement Making” below.
1.
Primary fuels = fossil fuels – coal and petcoke
These
provide the core heat and are used when the kiln is started up.
These help to maintain the high temperature needed for cement making.
Petcoke is itself a waste fuel.
(a)
Eg. SLF = secondary liquid
fuels – consists of waste oils, waste water and chemicals/solvents
from industry which are blended together to form the fuel. It is now becoming difficult to obtain enough SLF.
Cemex use up to 30% currently. This
is partly due to the fact that industry is trying to reduce
their waste output, so less SLF is produced.
Low SLF usage means more coal and petcoke have to be used and this leads
to greater pollution.
(b) Climafuel = paper and packaging waste – blended together.
There are plans to start using this in trials in the next 12 months.
Permission for this was granted in May 2005 (permission 1st
applied for in Jan 2003, has taken 2 and a bit years to gain this permission).
This is fast burning and has a low calorific density (ie. you need to
burn a lot of it to make enough heat). This
means more lorries are needed to bring enough climafuel in.
It will be good to have a trial of using climafuel as at present it is
unknown if this will be better or not. The
Environment Agency will hopefully analyse the results.
(c) Pelletised sewage – Human sewage contains heavy metals
which are not desirable on agricultural fields. Much of Europe has banned sewage spreading on fields
therefore it is thought that the UK will also ban this in the future.
Therefore sewage pellets for industrial use/burning
are an alternative way of dealing with our sewage.
The East Anglian Water Authority are looking at the possibility of making
and disposing of sewage pellets in the future and have approached Cemex, should
this legislation be brought about in the UK.
The
European Union Trading Scheme (EUTS) is looking at CO2 neutral
fuels in view of the Kyoto agreement. They
look at CO2 output versus tonnes of fuel burned.
In the future it may be a requirement to burn 20% biomass
derived fuels. Eg.
Pelletised sewage sludge, trees.
(d)
Tyres – Cemex do not currently have plans to burn tyres.
They may consider their use in the future, but they told us that the
supply was insufficient to be attractive to them.
Tyres contain iron which is a requirement of the cement making process.
Tyres also contain (Chlorine) Cl2 and sulphur.
Other plants in the UK already have permits to burn tyres.
Rugby cement are already trialing tyres as a fuel.
If tyres are burned at 2000ºC they produce mainly CO2 and H20,
however cement making needs a temperature of 1400ºC.
Tyres are now banned from landfill sites, so the Government is looking
for an alternative way to dispose of unwanted tyres.
The
advantage of burning wastes in a cement kiln rather than in a waste incinerator
is that the ash is captured in the cement clinker and becomes part of the
product. A waste incinerator
produces ash as a waste product which has to go to landfill sites, which in turn
increases the quantity of heavy metals in the soil.
Holland
has a plant which runs on 100% alternative fuels.
The plant has to apply to the Environment agency to burn alternative
fuels.
The
SLF is stored in a round steel tank. The
plant keeps only small quantities on site to minimise risk/also because they
cannot get enough SLF. The Chemical
Industry Standards state that there should be no sources of ignition nearby.
(eg. Watches, lighters,
phones).
At
present the plant is well within their limits for NOX emissions [oxides of
nitrogen = NO (nitric oxide) and NO2 (nitrogen dioxide)] from the
chimney stack. However, in 2008,
the plant will fail if NOX emissions remain at their current level, as more
stringent lower target levels are being set by the Waste Incineration Directive
(WID).
It
is feasible for Cemex to modify/refurbish their current plant to meet the 2008
NOX standards. However the wet
cement making process is inefficient compared to the modern dry cement making
process. Therefore in the long
term, it will be more economical for the plant to swap over to the dry cement
making process.
It
is understood that Cemex are world class on emissions.
The National Agreement on Emission standards has a maximum level of 50mg/
m3. Cemex tend to have
emissions in the range of 10-25mg/m3.
IPC
or IPPC (Integrated Pollution Control)
Look
at dust in wind
Sweep
cement plant site
Requirement
for crushing plant to be enclosed to minimise dust in the atmosphere.
It is important to look at emissions. (NOX/SOX/dust/furans/dioxins)
If
less fuel containing sulphur is burnt less SOX come out of the chimney (SO2
= sulphur dioxide). At present less
sulphur is coming out of the chimney and local farmers are therefore having to
put more sulphates on their fields.
This
currently uses a horizontal kiln which is 140m long and rotates. This kiln preheats, prepares and dries the raw materials to
produce cement clinker, which is then mixed with gypsum to produce cement ready
for concrete making. In Europe in
the 1970’s, vertical kilns were designed which are stationary (ie.
do not rotate), and use gravity, hence their desire for a very tall
pre-heater tower.
Needs
heat/temperature of 1450ºC in the kiln to make cement clinker.
Coal
and coke used initially to create this high temp.
Plant tries to minimize use of these fossil fuels, by using up to 40%
alternative fuels.
From
28.12.05 there is a new requirement of the Waste
Incineration Directive (WID), that the cement plant must measure the operating
temperature of the cement kiln. This
has not been measured in the past.
Mike Scott stated that he thinks the control room has
computers which can look at fuel temperature/pressure/fuel flows/SOX/NOX/dust
levels. It is possible to look at
trends in these things. Mike to
check if temperature is measured currently.
The liason group currently gets information on SOX/NOX/dust/dioxins/current
limits/including error bars to take account of uncertainty every 6/12.
He feels data should be given out more often.
(The accuracy of this data is to 3 decimal places).
The
cement kiln in Barrington is scheduled to stop twice in a year. The new kiln aim will be once a year. However there have recently been 50-60 stoppages in a year,
for 1 hour or more. It takes 24
hours for the kiln to cool down sufficiently to allow entry.
The
fuel input is stopped in a cement kiln breakdown or scheduled stoppage.
Therefore SLF’s are not put into the kiln if it is not at the running
temperature of 1450ºC. The staff
apparently know when it is at the right temp, through experience; the sound of
the rattling in the rotating kiln and the down time. Also brown/black clinker is
desirable and is produced when the kiln is at the right temperature.
If the clinker is white or yellow it is not hot enough.
The
new Rugby plant have suffered a lot of stoppages.
I asked how Cemex are aiming to avoid these teething problems with the
new kiln/plant. There have apparently been problems at Rugby, as they do not
have the raw materials on site, (this seems a rather feeble explanation!)
Chalk, marl clay, blue clay, iron pyrites (FeS) are needed.
99% of the raw materials are on site at Barrington making life easier.
·
Cemex are amongst the lowest users of alternative fuels in the World.
La Farg and Heidelburg used more alternative fuels.
There is a research lab in Switzerland which looks at cement and concrete
(but not pollution/dioxins).
·
SLF’s are burned in the USA and Europe. Cemex staff unsure where SLF’s are used in the USA.
·
The cemex staff were unable to tell us how they calibrate their stack
dispersion model.
The Environment Agency looks at Dispersion modelling.
There is no model of any
real value in the World. A study
was done to look at pollution at a site in the Fens and a site at Stansted
airport. Pollution dispersion is of
course dependent on wind direction and speed.
The liason group receives a Polar plot and this shows that the dominant
direction of wind is to the North East across Chapel Hill towards the north of
Cambridge. It is felt that
Haslingfield and Barrington should press for a dispersion model, which also
takes account of the air movements caused by the topography of the hill.
Dioxins/heavy
metals:
There
are 2 instruments used to measure dioxins.
1.
M cert approved continuous dioxin measurements – actually this is a
semi-continuous process. A
filter/resin trap is used and this is removed at intervals for analysis.
2.
A probe in the chimney – a sample is extracted isokinetically,
filtered and washed before analysis. This
is a tricky process and not very accurate.
Group
3 heavy metals can also be analysed.
The
Barrington SOX monitor which has now been removed recorded lower levels of SOX
that the one in the Fens. There is
now a new SOX monitor on the hill, which has also shown low SOX levels despite
being in the direction of the plume/prevailing wind.
·
Particle
sizes
– Measurements of PM10’s is possible. Cemex
do not currently measure particle size. There
is currently no continuous equipment available for monitoring particle size.
The National Air Quality Strategy 2003 put some limits on PM10’s.
(extractive sampling only). There is no legislation yet on monitoring of PM 2.5’s.
The liason group are pressing for particle size
analysis to include PM10’s, 2.5’s and 1.0’s.
(Need to check which of these particles will be trapped in the new bag
filters). There is an electrostatic
precipitator at Barrington Cement Plant which attracts particles.
The new plant will have a bag filter which is more efficient and works on
a similar principle to a vacuum cleaner bag.
The bag will be used for several cycles before being changed.
Volume
of particles has been considered by the liason group, rather than particle size
in the past. It is possible to
obtain a particle size distribution curve.
Diesel lorries/trains – these are also significant
sources for pollution.
Other
points/Miscellaneous.
·
It is unknown if Cemex have ever had a plant proposal turned down in the
past, and if so why this was the case. We
should also try and find out what modifications were required to their plans at
previous build sites, eg at Rugby.
The
Rugby plant does not have an aircraft light.
It is unknown at present whether the new chimney stack at Barrington will
require an aircraft light. (There
will be lighting behind the cladding for safety reasons around the chimney
stack, but the cladding should prevent most light pollution).