Mazingarbe
2 Voie Nouvelle
62670 Mazingarbe
GPS coordinates:
50.473306, 2.741688
At the foot of slag heap 49, transform a damaged site into a forest and seed orchard.
Types of Development
Nature area, reforestation
Agricultural Focus
Key Issues:
Renaturation
Green in the City
Agricultural Rehabilitation
Recreating environments conducive to biodiversity
Status:
Completion of the renovation
Project Overview
In partnership with the Commune of Mazingarbe, this project aims to redevelop a derelict site at the foot of slag heap 49, by combining the installation of a seed orchard, the creation of an urban forest and the creation of a soft pedestrian walkway. The project also includes agricultural reprofiling for recultivation. The circular economy of soil from local building sites helps to self-finance this natural, recreational, ecological and educational area.
Key Figures
Summer 2024
Soil contributions for 18 months
Autumn 25-Winter 26
Site development: paths, lookout point, information panels
Winter 2026
Planting trees, shrubs and lawns
Planted trees
agricultural area
ha
of nature space, including 0.5 ha of seed orchards, 1.1 ha of urban forest and 0.2 ha of slope afforestation.
Partners
Project Lifecycle
From a Contaminated Site to a Seed Orchard
October 2026 — On October 7, the ecological restoration project at the base of Sludge Pile 49 in Mazingarbe was officially inaugurated.
An inauguration attended by local stakeholders
The inauguration took place in the presence of Sandra Guthleben, subprefect of Lens; Laurent Poissant, mayor of Mazingarbe, accompanied by members of the city council; and Michel Marchyllie, executive director of Espaces naturels régionaux (ENRx). Representatives from the Hauts-de-France Nature Conservancy, the Mission Bassin Minier, the Chaîne des Terrils, and the social integration association Nœux Environnement were also present.
A seed orchard at the foot of the slag heap
Once a contaminated site, the base of Slurry Pile 49 is now home to a seed orchard with 1,250 trees, developed in partnership with ENRx. Protected by a forest buffer, it will help produce local seeds for the region. A trail open to the public now allows everyone to explore the site and see how it has been transformed.
The Circular Economy in Service of Nature
What sets this project apart is its funding model: inert soil generated by construction and public works projects was reused on-site, which made it possible to fully fund the development. This is concrete proof that construction debris can become a resource that contributes to the ecological restoration of land.
A new stage in the redevelopment of the site: the seed orchard sees the light of day
March 2026 – At the foot of slag heap 49, where mine tailings ponds once stood, a new ecological chapter is being written: the planting of an orchard dedicated to the production of local country shrub seeds.
Today, planting of the orchard’s 1,250 shrubs has just been completed. The aim is to produce seeds of European charcoal, one-styled hawthorn, buckthorn, viburnum, viburnum lantana, borage, blood dogwood and common hazel. The newly installed orchard is surrounded by a pollen barrier, which has also been planted. This new ecosystem is made up of 7,469 seedlings of field maple, black alder, common birch, walnut, wild apple, sessile oak, wild cherry, wild pear and small-leaf lime. The forestry plants are of course also of local plant origin.
The aim? To boost the production of regionally sourced plants and facilitate seed collection by nurseries and associations involved in the Local Plant initiative.
The orchard, designed in conjunction with Espaces Naturels Régionaux (ENRx) as part of a fruitful partnership, will guarantee the regional provenance of labelled produce – a key issue for ecological restoration and territorial resilience. The species to be grown in the seed orchard have also been selected in conjunction with ENRx, taking into account:soil characteristics,complementarity with other existing orchards, andlocal needs in terms of plant genetic resources.
The planting was carried out by the ASS NOEUX ENVIRONNEMENT association, illustrating the cooperation between local players in the service of biodiversity.
The end of soil inputs: a new step forward
November 2025 – The delivery of inert soil and the new landscaping have been completed. Planting will take place this winter: fruit trees in the orchard, a tree-lined pollen barrier, and wooded embankments. More than 7,000 locally sourced trees will be planted, contributing to the creation of a rich and sustainable new natural space. This new forest area and the greenway will be inaugurated in spring 2026.
Students visit Mazingarbe site: discovering an environmental requalification project
October 2025 – Students from the Junia Ingénieurs international Master’s 2 program in Lille visited the ECT site in Mazingarbe (62), where 5 hectares of severely degraded land are being redeveloped at the foot of slag heap 49. This project incorporates several environmental and innovative aspects :
- Containment of soil pollution to protect the environment and human health.
- Environmental remediation to restore soil and ecosystem quality.
- Combating invasive alien species to preserve local biodiversity.
- Creation of a seed orchard in partnership with Espaces Naturels Régionaux (ENRx).
- Financing through the circular economy thanks to the recovery of excavated soil from the local construction industry.
Mayor and elected officials of Mazingarbe visit the terril 49 requalification site
April 2025 – Mazingarbe’s elected representatives visited the ECT project at the foot of slag heap 49. In partnership with the municipality, this project is transforming a degraded site into a seed orchard and urban forest. Thanks to the reclamation of local excavated soil, 4.8 hectares will be rehabilitated at no cost to the community. An exemplary project, at the crossroads of biodiversity, the circular economy and service to residents and the region.
Mazingarbe, a study site for the ecological rehabilitation of mining sites
February 2025 – At the foot of slag heap 49, the ECT site in Mazingarbe hosts study plots for the European REECOL project, led in France by INERIS. This program aims to develop sustainable solutions for restoring degraded soils in mining regions.
The circular economy of building land at the heart of the transformation
November 2024 – Since the summer of 2024, excavated soil from our local partners’ construction sites has been transforming the landscape at the foot of slag heap 49 in Mazingarbe. Coming from a 22 km radius, the soil is part of a circular economy initiative to create an urban forest, a seed orchard and an agricultural area, while combating the Giant Hogweed. The traceability of inert soils is at the heart of the project: each input is controlled from source to final placement. A project that combines land reclamation and landscape rehabilitation, in partnership with local players and ENRx.
Rehabilitating the mining landscape through an ecological renaissance
Coal mining has left its mark on our landscape with the majestic slag heaps. These include terril 49, which has been transferred to the Conservatoire d’Espaces Naturels des Hauts-de-France for land protection. At the foot of the slag heap, the abandoned land is overgrown with various types of waste and colonized by invasive exotic flora, such as the dreaded Giant Hogweed.
The reuse of inert soil from local construction sites is an opportunity to rehabilitate this derelict land and transform the site. The transformation of the site is self-financed by the circular economy of inert soil, and will provide a natural space for relaxation.
This project has been designed with a multidimensional approach: ecological, landscape, sensory, well-being and educational.
4 project challenges :
- Creating an urban forest
- Building a seed orchard
- Maintaining agricultural land
- Opening the site to the public
