WSP has been working for British Gypsum since 2003 on two major manufacturing plants, one being a new bag plaster plant at East Leake, for which WSP was shortlisted for the 2007 IStructE Awards.
WSP provided multi-disciplinary services for the design of this £80m, new bag plaster manufacturing plant. East Leake is British Gypsum’s head office and the largest of their five UK manufacturing plants. It has been a busy operational site for over a hundred years and has grown up around a gypsum mine which continues to supply one of the main raw materials for plaster production. The new bag plaster plant which came on line in March 2007 has been created in the heart of this existing production facility.
The project comprised £30m of new build structures and extensions and alteration of existing structures to form part of a new bag plaster manufacturing facility. It comprises four key elements, including a new 35metre high, ten storey mill building housing the main process and control equipment, a 60metre diameter octagonal homogeniser, conveyor gantries and a warehouse. WSP delivered the services required to take the project from feasibility through planning to final construction.
The site for each of the new buildings was reclaimed by demolition of a collection of redundant buildings. The use of a congested brown field site was driven not only by environmental considerations but by interdependence with the existing production facility. The mill building and the homogeniser were constructed over an older area of the gypsum mine that had been worked using a pillar and stall methods with no regular grid. Geotechnical investigations also revealed voids in an unworked gypsum seam above the mine. This presented major challenges in the foundation design.
Piling through the mine was ruled out because of the potential to increase groundwater flows into the working mine. Grouting of the mine itself was impracticable due to the quantities of grout that would have been required. The cost effective solution that was developed involved drilling and grouting to improve the strata above the mine. The buildings could then be founded on shallow foundations.
Stepen Smith, British Gypsum Operations Director for the East Leake project, said,
“What we have achieved, on time and on budget, is a plant that has been designed to operate to World Class Manufacturing standards. To have the plant now recognised world wide for the excellence of its structural engineering is a real feather in the cap for WSP and for everyone who has been involved in the project”.
Client: British Gypsum