Knowing the deposit

The procedure:

- extraction of the materials through standard mining methods, located in or around the mining pit,

- production of materials, carried out in permanent facilities,

- shipping the products to the locations where they will be used.

Knowing the deposit

Discovery

Discovery

Before exploiting the rock, all of the unusable material recovered must be removed: top soil, all types of clay, carbonaceous shale, mixtures of unusable material.

Unusable material is removed and used to form hills several dozen meters high. The shapes and the planting are in strict conformance to guidelines for good environmental management. Several Million trees are planted each year. In addition, a thirty-year landscape plan was signed in 1994 for the Marquise quarry basin.

The Ferques quarry is located within the Parc Naturel Régional des Caps et Marais d’Opale.

Breaking the rock

In light of its substantial hardness, limestone cannot be extracted directly by mechanical means. The use of explosives to break away sections of rock is necessary.

Day and night, rock drills make vertical holes in the rock (more than 100 km per year) which hold the explosives and the equipment required to carry out the blasting.

Each blast produces a gross weight of 10,000 to 15,000 tons of rock. Safety of the blasts and total control of the environmental impact are of the utmost concern.

 Breaking the rock

Transport to the primary crusher

Transport to the primary crusher

The raw material consists of a mixture mostly of limestone with a block size distribution of 0 to 1500 mm but also includes small quantities of interstitial clay and a few large blocks which can weigh up to 10 tons.


Blocks over 6 tons are not able to go through the primary crusher and are broken with a rock-breaker or are separated to be used in the creation of harbor breakwaters.


The rest is moved to the crusher’s hopper over a distance which can vary between 200 to 2000 m from the source and and can vary in height, positive or negative, by more than 100 m.


The move is achieved with giant 1000 metric horsepower shovels and dumper trucks of more than 100 metric tons of loading capacity.