The Works in Ebbw Vale, South Wales combined green compost - taken from households in the local region of Blaenau Gwent - with colliery spill and basic steel slag to make 100,000 tonnes of its own soil. The method produced two types of soil suitable for either grassland or woodland.
The project - a partnership between the Welsh Assembly government and Blaenau Gwent Council - is the location for new developments including a hospital, post 16 education facility, leisure centre, theatre and up to 720 new homes.
The Works project director Richard Crook said: After 200 years of industrial activity on the former Ebbw Vale steelworks, natural soil cover had been lost. The entire site was a wasteland, devoid of vegetation and covered in [tonnes] of slag and colliery spoil where little could grow.
Steel slag was once an unwanted by-product of steel making but since ways of recycling it have been discovered, it has become a highly valued fertilizer in gardens and farms; as well as being used to make high performance concrete.
Deputy minister for housing and regeneration Jocelyn Davies said: The Works is one of the most ambitious regeneration projects ever seen in Wales and a leading example of sustainable development in practice. Virtually everything on the site has been recycled from the steel in the reinforced concrete to the concrete itself which was crushed to be reused on site.
"We want to make The Works at Ebbw Vale a future carbon neutral site, so to find out we are well on our way to this by recycling everything on site is great news."