Our production sites

To add value to natural resources you must first gain an understanding of the deposits and operational possibilities linked to the environmental, legal and social components. 

This is how the On-Jemelle and Merlemont sites go about conducting and developing the scope of their activities. 




Founded by Hippolyte Dumont in 1889, the Hermalle site was the starting point of the Lhoist Group. 

Our decision-making centers for the Group and for Western Europe, worldwide research & development and IT centers are based in the Walloon Brabant province. Wallonia remains therefore extremely important for the Group's management, but also for our family shareholders, who live in Belgium and remain extremely attached to it. 765 direct jobs and a considerable number of indirect jobs are generated in Belgium.

Both the European and Belgian activities are particularly important for the Lhoist Group. Indeed, Europe represents almost 60% of our global business, with Belgium still contributing about a quarter of the revenue generated by our European activities.

Press contact: press@lhoist.com

Lhoist’s Belgian industrial activities are split between 4 production sites:

Lhoist site at Hermalle (1889)

The activity of the Hermalle factory is a reference point for the transformation and calcination of both limestone and dolomite, which are required in many industrial sectors such as the steel industry, the production of refractory bricks, environmental protection and chemical industries. It is the second largest lime/dolomite factory in Europe.

The production facilities at the Hermalle site are exclusively supplied by stone coming from other Walloon factories: the Marche-les-Dames quarry provides the dolomite via the River Meuse and the Boverie quarry in Rochefort is the only site to provide limestone.

The factory's total production capacity is about one million tonnes of lime and dolomite a year.

The Hermalle site directly employs around 200 people. A study carried out in 2013 by UCL showed that 130 indirect jobs were generated just for outsourcing and supply activities for lime production.

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Lhoist site at Marche-les-Dames (1937) 

The Marche-les-Dames site specialises in the extraction of dolomite (magnesium limestone) essential for many industrial sectors such as the steel industry, the production of glass, the chemical industry as well as for agriculture and manufacturing fertilisers. Part of the dolomite which is extracted is brought to very high temperatures in kilns to produce sintered dolomite, used in the making of refractory bricks. 

The Marche-les-Dames quarry also provides Lhoist’s Hermalle site with dolomite for the manufacture of industrial calcined dolomite.

The factory’s total production is about 3 million tonnes a year.

The Marche-les-Dames site directly employs around 200 people.

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Lhoist site at On-Jemelle (1924)

The On-Jemelle factory uses limestone from the Boverie quarry, in Rochefort. The extracted stone is forwarded to the crushing unit. The Bovarie quarry also provides limestone to Lhoist’s Hermalle site. 

The kilns constitute the heart of the activity of transforming limestone to lime. Each year, 400,000 tonnes of lime are transported by lorry or wagons, mainly to customers in the steel industry or customers in the environment sector.

The On-Jemelle site directly employs 105 people. 

A study carried out in 2013 by UCL showed that 161 indirect jobs were generated by both the outsourced and supply activities.



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Site at Merlemont

The Merlemont Dolomite Quarry has been present in the commune of Philippeville for over a century and belongs to the Lhoist Group and the Yara Group.

The Merlemont Dolomite Quarry extracts the ocre/beige dolomite, crushes it and markets it under the GRAVIER D'OR® trademark. It embellishes the alleyways and pathways of parks and gardens thanks to its warm tones. The grey dolomite which is extracted and crushed is used for the manufacture of fertiliser.

The total production capacity of the factory is in the region of half a million tonnes of dolomite a year.

The Merlemont site directly employs 13 people and 37 people indirectly.


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