The chronicle of ground attack solutions: focus on aggregate extraction
The chronicle of ground attack solutions: focus on aggregate extraction
Focus on France's primary underground resource, aggregate, a material that is essential to our daily lives.
Aggregates: extraction, types and uses — an everyday essential
Already used in Antiquity, aggregates have long been the optimal solution for public works, civil engineering, and construction. Let’s take a closer look at France’s most extracted subsurface resource: the aggregate.
What are aggregates?
Also known as aggregate material, aggregates are rock fragments of various sizes. Depending on their dimension, aggregates are classified into the following categories:
- Fine sand
- Sand
- Gravel
- Crushed stone
- Ballast
Aggregates are further divided into families with distinct geological characteristics.
Aggregate families
Alluvial aggregates
Extracted from valley bottoms, formed through thousands of years of erosion and transported by rivers, streams, or glaciers. They often have a rounded shape — “rolled” aggregates — ideal for concrete compaction. The most common rock types: siliceous, limestone, and silico-limestone.
Crushed rock aggregates
Derived from volcanic rocks (basalt, rhyolite), plutonic rocks (granite, diorite), sedimentary rocks (limestone, sandstone) or metamorphic rocks (gneiss, amphibolite). These are extracted using explosives and then mechanically processed (crushing, grinding, screening, washing) to achieve the desired grain size.
Recycled & artificial aggregates
Recycled concrete and asphalt, blast furnace slags… produced by mechanical treatment after demolition. 10 % of the aggregates used come from recycling.
Aggregate extraction
Extraction methods vary depending on the deposit type. For alluvial deposits, extraction can occur in or out of water. For land-based deposits, excavators or wheel loaders equipped with large buckets are used. For solid rock deposits, explosives are used to free the material, which is then processed into crushed aggregates.
- Drilling + blasting followed by loading and transport to crushers (excavators, loaders & dump trucks).
- Non-blasting when materials are soft enough.
- Falling face method: undercutting at the base of the face so that materials fall by gravity (e.g., Maurienne).
Bucket equipment for extraction
Feurst® technical teams offer an online configuration tool to recommend the optimal bucket protection setup. We can also design a custom-made bucket according to extraction conditions (particle size, rock type, blade shape and thickness, adapter spacing, inter-tooth protection, etc.).
Objective: a specific recommendation combining abrasion resistance with enhanced penetration. A well-protected bucket reduces wear, fuel consumption, and preserves the machine structure.
Production & uses
Aggregates are essential: approximately 1 million tonnes per day are produced to meet the needs of the French economy. 80 % are used in civil engineering and 20 % in building construction.
Construction
Aggregates are a key component of concrete (reconstituted stone). Their strength and durability make them the most widely used material for houses, buildings, hospitals, bridges, and more.
Roads and pavements
Provide grip and stability for road surfaces, both in the foundation and in the asphalt wearing layers.
Railways
Ballast maintains track spacing and ensures rigidity and durability for trains and high-speed rail.
Conclusion
As an essential resource, aggregates are used in the construction of roads, streets, public squares, sidewalks, railways, and buildings (residential, offices, factories, schools, hospitals…). Their characteristics and specifications vary according to use: density, angularity, size, and granularity are key factors.