The Saint-Jacques slag heap comprises four million cubic metres of black schist from the Charbonnage d’Aiseau-Presles colliery. It was largely reprofiled in the 1970s and has been lying fallow ever since.
Artificial spaces recolonised by nature lay side by side with illegal waste dumps and degraded areas devoid of ecological value. Stability problems gave rise to risks of subsidence of the schist banks and the area became dangerous, particularly as it was used for uncontrolled quad and motorbike riding. There was an urgent need to take measures to counter nuisances that were harmful to the protection of the site.
At the same time, Belgarena, another company in the ROTON Environnement Group, was looking for an outlet for the soil processed by its own site. The project offered a unique opportunity to kill two birds with one stone, in a win-win operation upon which the group eagerly seized.