Restoration delivered at Piperhill
The opencast site at Piperhill in East Ayrshire has recently undergone a programme of restoration and rejuvenation.
Led by SMRT board member Ian Howat, the restoration project transformed the area from a bare, overburden tip, full of rock and rock dust, to a lush, area of grass, which has great potential for growth.
No materials were removed from the site in the process – instead the land was manipulated and made firmer and more fertile with the use of sewage cake, which allowed the area to be reseeded.
The work began in May 2004 following a full risk assessment of the site.
Ian and his team began preparation works by using a heavy disc harrow to break up the crust that had formed on the land, to create cultivated land, or tilth.
In consultation with the stakeholders involved in the process, it was decided that sewage cake should be brought in and mixed in with the tilth to create the best possible opportunity for growth.
The cake, supplied by Thames Water and delivered by a local sewage works, was stored in a series of lagoons.
A local agricultural contractor was brought in to spread the sewage cake, some of which was semi liquid, across the area, initially at a depth of two to three inches.
A chain harrow was used to mix the sewage cake into the tilth, and then created a seed bed, seeding the areas where the cake had been spread.
The project had benefitted from dry weather up until the seeding process began. However the weather deteriorated and there was a high risk of runoff, due to the steepness of the terrain.
After consultation with the operator, it was decided that the sewage cake coverage should be reduced to one inch to prevent this runoff.
This change was a success, and despite a considerable amount of rain falling in the few weeks that followed, the surface was rough enough to hold the material and prevent runoff.
Ian and his team were able to get back onto the site at this point and mix the cake fully into the soil. The area was seeded with a mixture of grasses and after about three weeks there was a good cover of grass, which helped to stabilise the soil, with very little runoff.
The Piperhill project demonstrates the type of work that can be done on an abandoned opencast mining site, creating a sustainable environmental solution for the surrounding community, as well as returning the site to its former use.