Donald, a caver with the Compagnons de la Nuit Minérale

Each month, we invite you to discover the Creil Sud Oise area in a different way through the portrait of 12 Tourism Ambassadors who act daily for tourism in the south of the Oise!

Donald Accorsi

Member of the caving club Les Compagnons de la Nuit Minérale

If Donald Accorsi has only one helmet screwed on his head, he wears 3 hats in the world of caving: he is treasurer of the caving club Les Compagnons de la Nuit Minérale, Chairman of the departmental caving committee (Oise) and Deputy treasurer of the regional caving committee (Hauts-de-France). For the past 40 years, this former member of the Institut national de l'environnement industriel et des risques, l'Ineris (one of whose fields of study is soil testing), explore, discover and rediscover the subterranean caves of the Oise, without ever tiring of it (and beyond!).

The Companions of the Mineral Night

The city of Caving club The Companions of the Mineral Nightbased in Senlis, was founded in 1985 by Donald Accorsi and 5 other underground enthusiasts. Today, almost 40 years later, between 35 and 40 members criss-cross the caves of the departmentAnd all over France and even further afield!

Speleology means "the science of the hidden world". This discipline developed at the end of 19th^th century and, in its early days, brought together mainly scientists. While some of them are still in Donald's team, the club also counts, Its members include photographers, topographers, hydrogeology and geology enthusiasts, lovers of underground beauty, sports enthusiasts and the curious.... with one thing in common: a passion for these hidden worlds.

This passion, cavers do not hesitate to share it regularly with the general public on the occasion ofIntroduction to rope accessorganised in Maysel, as well as at the sessions to discover the underground environment in a quarry near Senlis. Participants dive a few metres or dozens of metres underground, to discover the very special fauna of this worldand learn a little more about the geology of our region through observation of the different rock strata. And if they miss an inscription carved in stone by our ancestors in the 18^th Donald and his companions will not hesitate to attract their attention and test their ability to decipher a forgotten script!

Over the years, the Club's members have improved their skills and have carried out in-depth researchhave surrounded themselves and now offer comprehensive teaching materials (files, diagrams, videos, etc.) to schools for programmes on geology or the evolution of species. The media library is accessible on their website with a catalogue of over 2,000 books available!

A practice open to all

With around 40 members, mainly from the Oise and Val d'Oise regions (but also from the Cantal and Brittany), the club is open to everyone, whatever their level of rope climbing ability. There's no age limit for practising, and the proof is in the doyen, José, who, at 81, is still very active!

However, as caving is a very demanding activity during which you must always pay close attention to safetyYoung people under the age of 16 must always be accompanied by parents who are Club members.

Caving in Maysel

Once or twice a month, mainly at weekends, the Compagnons de la Nuit Minérale Club visits an open-air quarry in Maysel. This quarry is particularly useful for training, education and progress initiation. rope access and also accompany beginners while ensuring their safety. The walls remain accessible and can be monitored more easily than underground.

In addition to these monthly meetings reserved for members, the Every year in September, the Club organises an introductory weekend attended by more than 150 people.adults and children to discover this unusual (and little-known!) sport. Participants can move along one of the three stone walls equipped with spindles or drilled moorings, one of which is protected under a stone canopy in case of rain. This high point is also an opportunity to present the public with exhibition panelsl' The hidden face of the world, its unique fauna, the mysteries of geology and the work of stone-cutters and quarrymen, or the mushroom growers who have taken over the caves. You can also discover photos taken by Club members during their explorations in France and abroad.

To ensure an optimal experience and the safety of participants, the Compagnons de la Nuit Minérale regularly maintain the quarry and its walls and dispose of waste. And it's thanks to this work that the quarry is now suitable for rope access (15 years ago, it was a bramble patch!) and that it is less and less subject to incivilities.

Superheroes on unsuspected missions

It's rainwaterThe run-off is more or less intense, but particularly constant, that erodes the rock limestone as it passes through the cracks, then digs cavities. The Doubs, Ardèche, Alps, Hérault... all have beautiful underground caves that were created thousands of years ago. In the Oise, on the other hand, the limestone is porous and allows water to pass through without any preferential path.. It flows towards the water table, without ever creating a real passage. So how were the caves in the Oise visited by Donald and his companions created? By the hand of man! The Oise region has comparatively recent underground passages, because 100% artificial !

Oise, and in particular the south of the department, has provided stone construction sites for centuriessuch as Pierre de Saint-Maximin which helped build the Haussmann's Paris, the Tour Saint-Jacques, the Opéra Garnier... and this stone was extracted... from underground! This creates cavities as the blocks of stone are extracted. on their way to the capital. Over the centuries, More than 1,000 caves have been dug, and they abound in the subsoils of the Isère region.

These cavities, even if they are not subjected to the ravages of the rain, are sometimes subject to collapse which cause roads, land and fields to collapse. Donald and his team then intervene at the request of private individuals, town halls or the Departmental Council to probe basements, understand the nature of the ground, the nature of the collapse, produce plans of the cavities and establish an instability index. In 2020 and 2021, this mission enabled the Club to maintain its activity despite the confinements, in particular during the topographical surveys carried out in the basements of the communes of Saint-Leu-d'Esserent and Mello.

Discover the Compagnons de la Nuit Minérale programme