The Plaster’s stone-pit of Triel / Seine


Introduction -Lamps - Technique photo - Plaster's stone-pit - Refuges - Roucy - Paris - Tuffeau's stone-pit - Naours -Mushroom bed

- Abyss of Fage - Unusual - Biblio et contact


Plaster : sulfate of hydrated calcium ( CaSO4), mineral of the sedimentary rock, in monoclinical crystalline structure. Varieties : plaster " iron of lance " or "larkspur", plaster saccharoïde (in fine grains), fibrous plaster ( fine attached needles), plaster " rose of sands ", alabaster ( pure white plaster). Give some plaster (sulfate of lime) by cooking among 150 and 200°C. The plaster, added by gelatin and by colouring agents gives the stucco (artificial marble). The anhydrite is some plaster not containing water.







A walk in wood which dominates Triel will make for you guess the area of the damages. The numerous craters are in fact fall of stone underground very beautiful. They are rather impressive and leash to imagine the state of the stone-pits down. Moreover, the place is so unstable, that panels dissuade the careless walker. The footnotes of history wants that a day, a caravan and his owner were taken by a fall of stone as if they had been in a hourglass. (See the footnotes of history of the stone-pit of Triel's plaster below). It will make you reflect maybe before engaging you inside.



No carelessness so because this stone-pit, besides having of numerous fall of stone, is flooded and it is a true labyrinth. The plaster is a stone to soft that the water makes disintegrate in speed big "S". One can hear the plaster collapse) in " plic ", " splash ", " plouf " which are cold in the back. It is all the same possible to venture by being careful there not to get lost, because there will be nobody to look for you. Personally, I am not a supporter of Ariane's thread. If it breaks itself without that you notice it, you will have no more marks, as far as the number of threads roaming on the ground will help you not at all. The method of the " left wall " (please , follow all the time the same side  by a wall) will allow you in blow on to turn back at any time if the gallery sinks really too far. Don’t  write on the walls, the charm of the site would suffer from it. The film of plaster in the surface of the water in the light of flame gives to the frame highly-rated one magic.





The "Cathedral" doing no not less of 7m50 of height (measured with a rangefinder with ultrasound) here is to the left. Vaults are luxurious, and maintain the sky of the stone-pit. It is moreover one of the rare places about healthy of this cavity. A good part was struck during the exploitation to reassure and stabilize the zone.



Stone-pit of Triel / Seine

More photos



The footnotes of history of the Triel's stone-pit of plaster


 Being practised from the Middle Age to Chanteloup, to Triel-sur Seine and has Vauw-sur-Seine, the exploitation of the plaster goes out of the craft frame in the 18 s.: in the 1960's 1970, a million tons are extracted a year. Such extractions are not without consequences: they are fall of stone, localized and unpredictable collapses caused by a subterranean collapse, forming craters of variable dimensions. Under the massif the layer of plaster measure up to 7 to 8 metres in thickness. The exploitation was practised according to the method said about rooms and pillars with kilometres of galleries 7 metres wide: it results from it a big checkerboard extending over several square kilometres. To avoid waiting that galleries collapse of themselves in a inconvenient way, one practises henceforth the blowing up, technical consisting in provoking the collapse by blowing up a first line of pillars then successively the other parallel lines on a given surface. The collapse echoes at ground level by a collapse of 3 or 4 metres allowing to find a certain stability: a technique limited to the not urbanized zones. 800 hectares of underground are concerned.. Only 200 hectares were stabilised by the method of the steered blowing up... These collapses demonstrate themselves in a spectacular way: in 1991, to Chanteloup, under the eyes of powerless witnesses, a ground collapses, a caravan and a young man are immediately snatched. A Plan of Exhibition at the Risks ( PER) was set up since, without satisfying for all that the local residents and the concerned municipalities. The affair is in discussion since 1994. An association established(constituted) to follow the file: S.O.S. Stone-pits.






Surface: on 1558 ha

Population: 11097 hab. (1999)

Origin of the name: triellum ( three islands)

Hautil ( high island) massif in which are the stone-pits

The forest of Hautil covers 1250 ha and extends over several municipalities

The highlight of Hautil is 191 m and the average height of the forest massif is 135 m

The chestnut-tree is the dominant essence of the forest (60 %)

The oak and the ash tree are divided the quarter of the forested space.

Hautil is occupied since the prehistory, certain vestiges are there still visible (there, Le Furet  does not know where?)