The Aven Armand was unexplored for thousands of years. It is one of those pits that inspire terrifying legends and are accused of being devil's throats that swallow up lost travellers and wandering herds. We owe the discovery of this swallow-hole to Louis Armand, who explored it with Edouard Alfred Martel, the pioneer of speleology. Armand worked alongside Louis as an explorer both in France and abroad. On 18 September 1897, at the Hôtel des Voyageurs in Rozier, Louis Armand announced to Martel: "Yesterday when 1 was going down from the Parade 1 landed by chance on an master hole. The big stones that 1 threw down it went a hell of a long way and made an incredible amount of noise." On 19 September, Martel, Viré and Armand arrived on the site with a linge amount of equipment. As Martel described it: "A thousand kilos of ladders, ropes, telephone, camp beds, light cases, clothes, provisions and tools". Armand went down the 75‑metre vertical drop first without encountering any major difficulties. As soon as lie posed his feet on the scree cone, lie cried out "It's huge!" Then lie discovered the Forêt Vierge ( Virgin Forest) and telephoned to Martel: "Mister Martel, it's splendid! There are at least a 100 columns. The biggest must be a good 25 metres high. I have never seen anything like it. Come down and see for yourself".
The first expedition lasted for three days and during it they were also able to go 87 metres down a second shaft. Martel declared: "As the cavern didn't have a naine, I immediately decided to call it the Armand swallow-hole." Exploration continued over the following years. During this time, Armand organised private visits for amateurs who weren't afraid of going down the 75‑metre descent. Martel wanted to make Armand the director of a swallow-hole with suitable installations and fittings to receive the public, but was unsuccessful in finding the necessary financing for the project.
Then, three years later, two Toulouse entrepreneurs, M. Pin, M. Tondut and M. Paul, finally acquired the lands and necessary planning rights to carry out works to open the swallow-hole to the public. The Aven Armand public limited company was set up on 25 August 1925. The works started on lst June 1926. These were considerable.
They included : building a road linking the RN586 route to the Swallowhole entrance, digging a 208 metre long tunnel sloping gently down to main chamber, making a staircase so that people could circulate freely in the cavern and lastly, making paths around the stalagmites, lighting in four different colours.
The inauguration of the Swallow-hole’s installations for visitors took place on 11 June 1927. This was thirty years after it's discovery. The monument in honour of Martel and Armand was unveiled on the same day as the inauguration. This monument was erected near the Rozier Bridge in the Mostuéjouls commune.
The formation of the Swallow-hole Armand and its so particular stalagmites used two natural phenomena related to the evolution in the time of the karstic medium (Erosion and corrosion of the solid masses limestones) the digging of a vast cavity its partial filling by concretions (stalactites and stalagmites).
The creation of the cavity is the result of the dissolution of the calcareous rock by acid water. The rainwater is normally not acid, but will acquire this acidity, initially while crossing the atmosphere, then and especially while percolant through self where they grow rich out of carbon dioxide (CO²), resulting from the bacteriological activity on the organic matter (plants, animals, etc...) Penetrating in the rocks limestones by their cracks, it impregnates it and hollow by dissolution of the cavities of size and variable forms. The evacuation of the dissolved products is ensured by the circulation of water towards the low parts of the relief here the valley of Jonte. The initial cavity, started once, can increase by collapse of its vote weakened by corrosion.
The formation of concretions proceeds of the same process of dissolution, but when water charged with limestone dissolves meeting an aired cavity, carbon dioxide escapes releasing the limestone which will settle with the vault by forming stalactites and eccentrics on the walls by giving draperies and discs on the ground by forming gours and stalagmites.
At the Aven Armand, water, particularly rich in dissolved carbonates, forms with the vault of the very heavy drops which do not remain long enough with the ceiling to form important stalactites. In addition the great drop height (more than 40 m), accelerates de-gasification causing a carbonate supersaturation of the drop which while arriving on the ground explodes in innumerable droplets releasing their important mineral load who will crystallize all the more quickly around the point of impact. This precipitation causes the formation of dinner plates, whose diameter, function of the contributions of water, follows the seasonal variations of external precipitations. The development of the "sheets" and the "wings" is done then by capillarity (migration of water towards the periphery where it evaporates more easily).
E.A. Martel was born in 1859, in Pontoise, very early in life lie developed a passion for geography and the underground world.
He followed a career in law, which did not prevent him from pursuing his vocation as an untiring explorer. The many objects brought back from his journeys throughout the world and his works rapidly won him recognition as an expert on natural phenomena.
In 1883, he discovered the "Grands Causses" with as majestically beautiful gorges and magical underground sculptures. From that tune onwards he incessantly explored all "original new phenomena". He shared his knowledge with the general public through his publications.
He also encouraged making these places accessible to visitors by making suitable installations.
Image above : statue representing Louis Armand.
Louis Armand was born on 23 August 1854 in Parache, in the Vabres commune(Aveyron). He trained as a locksmith in Aguessac and then settled down in Rouer. In 1888, Martel needed someone to repair a small dismountable boat and on the advice of a friend contacted Armand. Satisfied with how he did the job, Martel enrolled him in his team. In 1889, lie was promoted to the post of foreman. For 20 years, Armand was Martels right‑band man in most of his research work in France and abroad.
From 1889 onwards, the Club Alpin Français entrusted him with ensuring the installation of the difficult passages at Dargilan, Rocher de Capluc, Ermitage Saint Michel and other sections of cornices in the Tarn and the Jonte.
Between 1898 and 1899, lie was responsible for the building of the enormous 36 metre‑high iron staircase in the Padirac cave. Up until 1907, lie acted as a guide for amateurs who wanted to visit the swallowhole.
In 1914, the outbreak of war put a sudden stop to his activities. He died of illness on 22 January 1922.