The New York Times reported on July 6 that "marnieres” — abandoned underground chalk and limestone quarries in Normandy, France — are collapsing by the hundreds in the wake of heavy rains. One collapse killed a man June 29, while other collapses have damaged houses, roads and fields.
Marnieres have been buried under farmland for more than a century after their entrances were plowed over. Very few were documented or mapped, the Times reported, either because miners wanted to avoid paying taxes or because the mines predate mine regulation. Heavy rains this spring melted the aging chalk pillars and ceilings of hundreds of mines, causing them to collapse and create craters and fissures at the surface.
On June 29, Sebastien Elerbach, 24, was at his sister’s house in Neuville-sur-Authou when he heard a crashing sound outside. He stepped into the backyard to investigate and fell into a 40-foot hole. Despite weeks of digging, his body was never found.
Elerbach is the only casualty so far, the Times article said, but 20 houses have been condemned. An estimated 140,000 caverns and tunnels are located in Normandy, ranging from a few cubic feet to the size of a gymnasium. But, the Times said, no one knows exactly where they are or how stable they are. The quarries were originally dug to reach chalk and limestone 30 to 150 feet below the surface. Farmers sank narrow mine shafts and then hauled out limestone to use in reducing the acidity of topsoil. The first mine collapses happened six years ago, when a handful of holes opened up in residential areas. In 1997, an entire house disappeared into the ground. With the onset of fissures this spring, local political leaders are proposing that the government compensate homeowners if their property is condemned as a result of a marniere.
Emily D. Johnson