It is a “nugget” unknown to the general public, 45 km north of Nantes. An almost lunar landscape, dotted with bumps, dominated by a cone of gray earth culminating at an altitude of 121 m, making it the highest point in the Loire-Atlantique * department. The old one
Abbaretz mining site, between Nort-sur-Erdre and Châteaubriant, reopened at the start of summer with new facilities and a secure route.
The site, very popular with hikers, BMX practitioners and motocross enthusiasts, had been largely closed in 2019 by prefectural decision. The state wanted to protect visitors from exposure to arsenic, a highly toxic substance. Abnormally high levels have indeed been observed in the soil, ponds and dust.
A legacy from the 1950s, when this area of Abbaretz was exploited by an open-cast tin mine. The accumulation of waste rock (unwanted minerals) formed the now emblematic slag heap. An adjacent board is also made up. Then after the precipitous closure of the mine in 1958, following a drop in the price of tin, these materials remained in place. Nature (mainly birch and heather) has gradually taken back its rights. As for the extraction site, 40 m deep, it has become a pond open to swimming.
“We can even see the Tour Bretagne”
“There was a health risk in leaving the entire site open. The return of the public was only possible with works and the establishment of a marked path with fences, ”explains Jean-Pierre Possoz, the mayor of Abbaretz. If access to the slag heap is still authorized, the spectacular plateau of mining waste can no longer be crossed, only approached. “We had to explain it to regulars, especially athletes. We must also do the same with the curious who venture there. “
Signs warning of “danger” have been installed, as in front of this disturbing orange pond where the vegetation seems to have literally burned out. “In this place, there is no more life because of the hyper acidity of the water and the soil. You will not melt in 30 seconds but it is indeed dangerous. The signs are not exaggerated, ”notes Jean-Pierre Possoz.
The walk, facilitated by footbridges, is nevertheless very pleasant. The highlight of the show remains the rise of the slag heap, after having swallowed some 200 steps. At the top, a very wide panorama emerges in good weather. “The view is superb indeed. You can even see the Tour Bretagne in Nantes, ”comments Michel, retired. “It’s a very surprising place,” confirms Elisa, her daughter. At times, it feels like on the moon or in an American desert. And there is this hill [le terril] that comes out of nowhere. I had heard of it before, but we had never stopped there. I will advise my friends to come back for sure. “
“No desire to attract crowds”
Before the work, the old tin mine was frequented by nearly 10,000 visitors per year, estimates the town hall. If the presence of the site constitutes a “brand image” for the municipality, it does not derive any significant tourist benefits from it. “We are away from the village and, apart from the nautical base, there is no major infrastructure to spend the day, justifies the mayor. We plan to create a path to connect it to the station [TER]. But there is no will to attract crowds. If there are too many people, the trails may no longer be respected. “
As for the mining activity, it seems definitively stopped, despite the obtaining of an exclusive research permit. by the company Variscan Mines in 2015. “They did a few polls and after four years they gave up. The deposit is not sufficient. Nearly 4,000 tonnes of cassiterite (tin ore) had been extracted by the old mine between 1952 and 1958.
* The natural culmination of Loire-Atlantique is located in Fercé, near Châteaubriant. It is the hill of Brétesche (116 m)