Unusual black pyramids in Pas-de-Calais

In the Pas-de-Calais region, two black pyramids rise from the flat agricultural lands of the former mining basin, creating a striking contrast with the surrounding landscape. These structures, known as the twin spoil heaps of 11/19, were formed by the accumulation of 70 million tons of black shale, a byproduct of coal mining that was previously considered waste.

UNESCO recognition of spoil heaps

The spoil heaps, now classified as part of the UNESCO World Heritage for the Nord-Pas-de-Calais mining basin, have created an unusual microclimate due to the dark shale's ability to absorb solar heat. This has resulted in a warm and dry environment similar to that found in southern France.

Mediterranean species in northern France

The microclimate has allowed the settlement of Mediterranean species such as lizards, garrigue orchids, and thermophilic butterflies, which are typically found in regions further south. The black shale, which absorbs more solar radiation than conventional soil or green meadows, has created conditions that are significantly warmer and drier than the surrounding areas.

Ecological reclamation site

The site of the twin spoil heaps of 11/19, now one of the highest in Europe, has become a symbol of ecological reclamation. The artificial relief created by decades of coal mining has been transformed into a true open-air ecological laboratory, attracting both curious naturalists and hikers.

Contrast between human and nature

The contrast between the deeply human and industrial origin of the site and the biological richness it now shelters is particularly notable. The black shale of the spoil heaps, heated by the sun, has become a refuge for species that would never have been able to thrive under the local climate.