Key steps

Obourg's chalk reserves will be exhausted by 2034. But we have significant limestone reserves in the Tournaisis region. Their physico-chemical characteristics, and in particular their very low water content, make it possible to change the clinker production process to the "dry process" (instead of the current "wet process"). As a reminder, clinker is the main constituent of cement, which we market and use to manufacture concrete. 

This new kiln, coupled with the supply of limestone from Tournai-Antoing, will save considerable amounts of fuel thanks to its process and the low water content of its raw materials. We are planning to reduce the kiln's thermal consumption by almost 40%, and thus reduce by the same amount CO2 emissions per tonne of clinker produced. In view of the rising price of CO2 on the closed European ETS market (emission quotas) and the inflation of energy costs, building a new kiln is essential to control our production costs and therefore withstand international competition. 

We are also anticipating the forthcoming tightening of environmental regulations on industrial atmospheric emissions. These new regulations call for major investments: they only make sense in a long-term perspective, for new equipment and a new process. 

Finally, this new kiln opens the way to new technical developments to improve environmental performance. In particular, the use of pure oxygen (rather than ambient air) is necessary to implement CO2 capture techniques in the future.

We have chosen to build the new kiln on the Obourg site. This allows us to reuse and valorize part of the existing infrastructure. 

The new 'GO4ZERO' kiln will be built on the site of the current slag stocks. It will therefore be 150m closer to the residential areas than the current chimney. We are taking great care to drastically reduce noise, visual and olfactory impacts in the design of the installations, not only to avoid creating any additional nuisance for our local residents, but also to further limit the impact of our activities. 

We work with specialized engineering firms to reduce all potential sources of nuisance at the source: choice of machinery, appropriate location of noise sources, soundproof cladding, treatment of flue gases and containment of storage or unloading facilities for corrective agents and alternative liquid and solid fuels... Nothing is left to chance.

The new kiln replaces the two old ones, with a production capacity equivalent to the current one. The implementation of new technologies and the storage of raw materials in closed buildings will, however, increase the built volume. In particular, the preheating tower will have imposing dimensions, inherent to the "dry process" and to the dimensioning of the associated equipment in order to reduce the overall thermal consumption of the furnace and enable efficient combustion.

The tower will be approximately 140 meters high (the design is still being finalized, as this is a completely new combustion concept). It houses the equipment for decarbonating the material, the precalciner. The precalciner is the first part of the new clinker kiln and comprises a succession of cyclones, static heat exchangers that preheat the raw material (known as raw meal) and decarbonate it at over 850°C. The material, separated from its CO2, then enters the second part of the kiln, this time rotating and slightly inclined, where the raw meal is heated to over 1450°C for clinkerization. The preheating tower is an integral part of the dry clinkering process. 

The chimney runs alongside this tower and slightly above it. A great height, combined with a high gas ejection velocity, ensures even more effective atmospheric dispersion.

Today, the smoke coming out of the chimney is largely composed of water vapor and CO2. The water vapor condenses depending on weather conditions, and a whitish cloud is usually produced, the color of which is mainly influenced by the orientation of the sun. The use of the new dry process furnace, due to the very limited amount of water in the raw materials, will therefore result in a much less visible cloud of steam. 

In addition to water vapor and CO2, we will always find the same components in our chimney emissions, mainly resulting from the inevitable combustion in the clinkerization process. However, new equipment incorporating the latest technologies available on the market will be installed to significantly reduce the presence of these pollutants, further improving current performance. 

Lastly, the chimney height of the GO4ZERO project will be higher than today's, enabling better atmospheric dispersion.

To feed the new kiln, we need to receive around 65,000 tonnes of limestone per week from our Tournaisis quarries. This implies an average of 30 to 32 trains loaded with 2200 tons per week, entering and leaving the Obourg site. The Obourg site will be designed to accommodate this flow in complete safety, using the latest noise-reduction techniques and with the least possible operational constraints. 

Unloading operations must be able to be carried out at any time of the day or night, although Infrabel guarantees us a sufficient number of train paths to operate between 6 a.m. and midnight under current operating conditions. Night trains will therefore be complementary and used as a last resort, depending on the traffic hazards encountered during the day. 

The risk of noise pollution is mainly linked to the train unloading operation, at over 2,000 tonnes per hour. In fact, the shunting locomotive on site will be an electric robot, whose motors by their very nature produce virtually no nuisance. We are also considering the possibility of using locomotives that combine electricity (on the Infrabel network) and battery power (on non-electrified sites), operating at very low speeds and without jolts or powerful braking. We are able to limit the noise pollution caused by our rail activities, thanks to the appropriate design of the track devices, the track laying on our site and the automated unloading installations. Unloading, in particular, takes place in a concrete pit located inside a building designed to incorporate the best possible acoustic insulation solutions. 

On a positive note for our neighbors in Obourg, operation of the chalk quarry - and its possible nuisances, although under control - will come to an end once the new furnace is fully operational.

The layout of the main equipment, which has a high acoustic power, has been studied in order to find the best compromise between reducing noise dispersion towards the most exposed neighbors and optimizing the production process. From the outset, we included building soundproofing techniques in the specifications to reduce noise at its source. 

Acoustic dispersion models were produced as part of the impact study. We take into account the recommendations made by the engineering office in order to reduce our impact on the environment. In particular, we are taking great care with the unloading of materials as soon as the trains enter the site, by carefully choosing the techniques for installing switches and track, taking advantage of the experience of Infrabel's acousticians, and also by designing the building where the unloading will take place. The latter will of course be heavily soundproofed, thanks to a judicious choice of construction techniques and specifications on insulation materials and thickness. 

The choice of rolling equipment also takes into account the "noise" dimension: preference for electric/battery-powered locotractors, battery-powered automated robots for on-site handling, smooth operation at very low speeds, ...

Transporting limestone from Vaulx to Obourg by rail will generate CO2 emissions of around 5,000 t per year.

This project aims to secure the site's activity, and thus jobs, for the next 60-70 years.
The project also has the potential to generate additional business: on the one hand, through the construction of the new kiln and, on the other, through CO2 capture and treatment, which are future-oriented businesses with great prospects. 

Additional training initiatives will be undertaken to support staff in the use of new technologies. 

The construction of the site itself will help maintain and even create new jobs for the companies involved in this historic project.

The smells sometimes perceived today on the Obourg site are linked to the open-air storage of sludge and correctives. As part of the project, correctives will be stored in a hall at the site entrance, and liquid and solid fuels in halls and tanks with appropriate air treatment. As far as sludge is concerned, there will no longer be any temporary storage or pre-treatment, but only hoppers for direct feeding to the furnace. 

Generally speaking, olfactory nuisances will be totally under control with the new equipment and measures planned as part of GO4ZERO.

With only 5% additional trucks at most, the impact in terms of traffic will be very low, especially as all the heavy traffic is directed towards the industrial road, dedicated to heavy traffic, and access via the Obourg road, for traffic < 3.5T. 

It should also be noted that the Chemin du Pont d'Haine, which links the Route d'Obourg to the Route Industrielle, running alongside the cement plant and COMET, will be partially privatized and declassified as part of the permit application (specific file with joint public inquiry), along the entire length of the new plant, from the Rue des Fabriques entrance to the new development by IDEA, near the COMET site. The road will be closed on both sides and access secured. 

The procedure for decommissioning roads and old byways that disappeared 50 years ago will be carried out at the same time as the permit procedure. The municipal council of Mons has endorsed this request.

Repairs to the industrial road have already been undertaken, but we are well aware that in-depth work is needed to recondition it. 
We are currently in discussion with the city of Mons on this issue.

The road will be part of the factory. Private cars will enter via Bois Doyen and the railway bridge, and trucks will enter via the industrial road. For obvious safety reasons, neither cars nor trucks will be able to cross the plant.

The possibility of building the clinker production facilities close to the limestone deposits in Tournaisis was obviously studied, but the immediate proximity of housing and the available surface area of less than 30ha would have meant additional difficulties in implementation. And all the more so as our ambition goes beyond the new clinker manufacturing process: we want to prepare for the future and become carbon neutral. This will require equipment that takes up a lot of space, and the 80 hectares of land we have at our disposal in Obourg allow us to envisage a whole range of highly innovative industrial solutions that will bring new economic developments to our region. What's more, we don't want to multiply our footprint by developing new industrial sites. On the contrary, we want to continually improve our existing facilities and reuse equipment that is already available and in good condition. This will enable us to save on investment costs as we develop our project in Obourg, while creating greater economies of scale between the future clinker production unit and the existing grinding and shipping facilities. 

GO4ZERO is our plan A. It's a major technological innovation that is undoubtedly the most appropriate way of producing clinker in the future, while reducing the associated carbon footprint. There is no realistic and feasible plan B.

This has not yet been completely decided at this stage, but meetings are planned with the Nature and Forestry Department; we're trying to get their recommendations as far upstream as possible. 

We also intend to make arrangements at the top of Bois Doyen to minimize the tower's impact on the neighborhoods that will be most affected visually.

The project team will be happy to provide anyone interested in finding out more about the project in its current state of development. We will keep the web page up to date and communicate transparently with our stakeholders. Any questions can be addressed to GO4ZERO-be@holcim.com.

Holcim's carbon neutrality in Belgium is defined in terms of its reported CO2 emissions under, what is called, the 'ETS' system to which it is subject. 

In addition, Holcim is developing solutions to reduce its footprint for scopes 2 and 3, which are significantly lower than direct emissions (scope 1).