Abstract:
Woodsmith Mine, located near to Whitby in North Yorkshire, is a deep potash and polyhalite mine. A sensitive project, having attracted many objections along the way, developing the mine to extract the material from 1.5km below the moors with minimal impact, was always going to require some complex ground engineering solutions. To comply with planning the mine also had to be low impact, which restricted it to having only two 60m deep chambers to house the headgear for the production and service shafts and a 37km long tunnel to take the material directly to port facilities at Wilton on Teeside. Three shafts were required from ground level at Woodsmith for production, services and one for launching the 5m diameter tunnel boring machines (TBM) that will drive the first section of the 37km material transport system (MTS) tunnel at 360m depth from Woodsmith to Teeside. Bauer Technologies was appointed to install three up to 120m deep diaphragm wall shafts, with diameters between 8m and 35m. The shafts were formed by 2.8m wide and 1.2m thick panels - 48 for the service shaft, 44 for the production shaft headgear chamber and 14 for the deep main shaft. The extremely challenging ground conditions demanded three cutters on the project; (two MC96 machines and an MC128 carrying HDS120 hose drum systems and BC40 cutter units). Two BE500 and one BE550 de-sanding units fitted with BDS125 de-silters and a BD90 decanters were also used. Bauer has had to use shorter, larger diameter silos for the bentonite plant and also paint them a specific hue of green so they blend in. The plant was probably the largest in the UK with 1, 600m³ /h desanding capacity and 4, 000m³ of bentonite storage. The paper discusses many such construction challenges and technologies adopted at site in completing the project.
Abstract: Theme 8