In Saint-Colomban in Loire-Atlantique, two sand quarries already extract 700,000 tonnes of alluvial sand per year over more than 100 hectares. GSM and Lafarge, the operators, would like to exploit an additional 70 hectares, almost doubling the size of the quarries. Problem, this would be done on land classified as “perennial agricultural areas”, and local opposition is strong.
“The sand pits are three kilometers away, but they will probably meet in the long term, which would represent 300 ha exploited, because there is a strong demand for concrete in the region”, worries Benjamin Boileau, member of the collective La tête dans the sand. The stakes and the harmful effects on the environment are numerous: consumption of agricultural land, drying up of water resources, rise in land prices, loss of biodiversity, landscapes dotted with “gigantic water holes” surrounded by merlons of earth …
Extracting at sea, the worst solution
“More than a ‘consumption’ of land, we consider our operation as a ‘loan’,” argues Loïc Leuliette, communications director of Lafarge France. Once exploited, “the land is quickly rehabilitated to give it back an agricultural vocation whenever possible,” he explains. But for the opponents, “to find agricultural land with the original qualities is illusory”.
However, the sand is necessary for the construction and represents a real economic opportunity. “If the sand comes from further away, we multiply the trucks. If it is extracted at sea, we destroy the marine ecosystem. However, in the Pays de Retz, the construction of 1,600 housing units per year has been programmed, and one housing unit is 200 to 300 tonnes of sand. Tell me how to make housing without sand? », Asks Patrick Bertin, the mayor of Saint-Colomban. It plans to consult its population on January 9.
In Loire-Atlantique, the sanding of vegetable crops to promote growth and mechanical collection, also raises many questions. When questioned, the Nantes market gardeners federation evokes an “ancestral essential, stable and hyperoptimized” consumption of around 500,000 tons per year.
350 million tonnes per year in France
Second most exploited natural resource in volume after water, with a demand that has tripled in twenty years, according to the UN, sand is used in the composition of concrete, glass, microprocessors, roads, fertilizers, tires, paints , cosmetics, etc. France thus consumes 350 million tonnes of aggregates per year for construction.
“We consume too much sand in the world,” warns Eric Chaumillon, professor of marine geology. “It is not sustainable for a non-renewable resource that takes at least several millennia to form,” he continues. Problem, for Jean-Christophe Gavallet, president of the FNE of Pays de la Loire, “sand is still too inexpensive to justify innovative policies for the search for alternative materials”.