Silmer to the Hourdel is the calcination 72

On the barrier of Cayeux-sur-Mer, four companies exploit deposits of cobbles Marine to exceptional physical and chemical qualities, after sorting, crushing, or cooking, entering in the composition of the ceramics, white concrete, abrasive paper, industrial soils or road markings.

Since the cap D'antifer, in Normandy, to Ault-Onival, in Picardy, the coastline consists of chalk cliffs pricked of flint kidneys. By eroding the White Rock, waves released these Flint sea rolls in pebbles (from 2 to 20 centimetres in diameter) for thousands of years. Ocean currents and tides resulting to the North, they are accumulated for more than five thousand years against the first met obstacle, the left bank of the Somme between Ault Bay, Saint-Valery-sur-sum and Le Hourdel.

In this triangle, geologists estimate the contribution of the sea each year to 30,000 cubic metres of pebbles. It was the unique hard rock of the region used since the 16th century in the walls of the roads, the ballast of ships and the construction of houses and churches (one of le Tréport, including). Early 20th century, to supply company Delarue of Dieppe, collecting pebbles for the grinding of ceramic paste collection grows to Cayeux-sur-Mer. The port at Saint-Valery-sur-sum pebbles exports in England of the marine pebbles which the outstanding silica between in the composition of fine porcelain.

The operation of the roller of the Bay of Somme lasted until today. "It is a unique deposit in Europe." These pebbles silica is almost pure (98.3). They are totally resistant to acids, bases, salts and oil. Their physical and chemical qualities are very varied. "Hence the existence of an industrial hub of the roller to Cayeux-sur-Mer and the Hourdel", says Ludovic Legay, Director of the Baie de Somme of the GSM group sector.

It operates in the Hourdel since 1980, a career fossil cobble and marine sands of 88 hectares. She screened and crushed each year 220,000 tonnes supplying three local businesses: society Silmer (Group Gagneraud father & son), society Delarue (Group Sifraco) and the Chatelet (subsidiary of GSM) plant. This pole four has 132 employees and carries out almost 15 million euros of turnover by exporting in Europe mainly 60 of its natural and industrial production. The Chatelet plant dry and Thames (13,000 tonnes per year) in fine gradations from sand milling of the fossil deposit of GSM sea pebbles. Its products are used in the filtration of water, the sand blasting and stripping, special concretes, poultry (gravel) and the production of paintings and abrasive papers. Company Delarue sorts industrial Pebble (55,000 tonnes of 2-20 cm in diameter) with a very high hardness. They are used in grinding ball in the micronization of minerals and industrial ceramic paste activities.

Silmer to the Hourdel is the calcination (72.000 tonnes) of the most beautiful fossil pebbles, a special blue expressing the purity of silica. "It is the highest valuation to the Pebble," says Bertrand Sannac, Director of the plant Silmer in Cayeux-sur-Mer. Calcined to 1,600 C, these pebbles produce the cristobalite white snow, which, after grinding, is used as the raw material of the earthenware known as English, as paintings murals or road, plastics, resins, rubber or glues. "Sold more than EUR 200 per tonne, cristobalite of high temperature is also used to fine metal polishing and coating of prefabrication. Sole producer in France, Silmer, Cayeux-sur-Mer, in factory 15,000 tonnes per year with 60,000 tons of clear aggregates, calcined at 900 C, are used in marking of pavements (reflection), the stone and architectural concrete. "Some alternative products exist today, such as logs of aluminum or those of zirconium, but their cost is 12 to 15 times higher than that of the operation of the Cobbles", emphasize GSM and Silmer frameworks.

Businesses must return to dams operated by more vulgar pebbles volumes. Industrial visibility does not exceed three years taking into account the environmental approvals. In fact, today seek them with communities in the industrial pole of sea roller sustainability solutions.