Andalusite production in Glomel: reconciling strategic and environmental challenges
Nestled in the heart of Brittany, Glomel is home to a priceless geological treasure: an andalusite deposit of exceptional quality, mined by Imerys for over half a century. Let's find out more about this precious "Breton pink gold", from its extraction process to its many industrial applications, and Imerys' commitment to responsible, sustainable mining.
A quarter of the world's andalusite production comes from Glomel
Located in Côtes-d'Armor, Brittany, Glomel is one of Imerys’ 32 French sites. The Group has been mining a world-class 450 million-year-old andalusite deposit there since 1970, which is exceptionally rich in andalusite. The quarry comprises three pits, one of which has been in operation since 1998, and another used to recycle water. A project to open a new pit is currently at the analytical stage.
"We are the only andalusite-producing site in France and Europe," points out Christelle Planque, Site Manager. "Every year, we produce 65,000 tonnes of andalusite, which represents 25% of global production.” The Glomel site employs around one hundred people and serves more than 150 customers worldwide, mainly in Europe.
Andalusite, a material of choice for high-temperature industrial processes
Described as "Brittany's pink gold", andalusite is a mineral that forms when certain rocks are transformed by the effect of temperature on granite massifs (contact metamorphism). Very rich in alumina, this mineral has excellent resistance to heat, thermal shock and mechanical stress. Andalusite is therefore a refractory material used in a wide range of industries, including foundries, the steel industry, cement works and the production of ceramics, glass and aluminium. In particular, it is used for moulding steel and lining industrial equipment subjected to high temperatures.
The andalusite production process
Andalusite from Glomel is extracted and purified using a range of processes carried out on site.
Once extracted, the blocks of ore are sorted using excavators, then transported by truck to the plant, where a jaw crusher reduces them to a size of 30 centimetres. "These blocks are fed into a ball mill. This stage enables us to free the andalusite from its shale gangue," explains Julien Charroy, Production Manager. The grains from the crusher then undergo several separation and purification processes to eliminate fine particles, magnetic minerals, quartz and pyrite.
Exacting Quality Control
The product obtained is sent to the laboratory, where a team of technicians carry out various analyses on it:
- Densimetric, to determine the andalusite content;
- Chemical, to quantify key elements such as alumina, iron and alkalis, which are characteristic of the material's refractory properties;
- Granulometric, to assess particle size.
"The aim of the laboratory is to provide a statement of product conformity in relation to customer requirements," explains Alice Saget, Quality and Laboratory Manager. The site's quality department is ISO 9001 certified. The andalusite produced at Glomel is bagged in the form of sand or granulates and then transported by road or sea to Imerys' customers, who use it to manufacture bricks or concrete.
Glomel andalusite, a responsible, sustainable operation
Imerys strives to limit the impact of its activities on the natural environment. At Glomel, this commitment is reflected through a range of actions. "Our site's priority is the treatment and management of our wastewater discharge," explains Quentin Goutaloy, Environmental Technician. "We analyse the biological, chemical and hydraulic indicators of the bodies of water around the site rigorously to ensure that they are in good ecological condition.”. Imerys also regularly monitors its noise, vibration and dust emissions, which are governed by a prefectural decree.
In addition, Glomel's teams work in close consultation with local residents and elected representatives through consultative committees, site visits and the development of partnerships with associations. "We are proud of our production facilities. We are also very proud of our commitment to the environment, and the good relationship we have with our local stakeholders," concludes Christelle Planque.
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