In North Yorkshire, one of the UK’s deepest underground mines is being constructed by Sirius Minerals Plc over the next five years. The mine will extract polyhalite, a high-quality organic fertiliser consisting of the minerals calcium, magnesium, sulphur and potassium. The project is unique because all mining and transportation operations will take place completely underground, once the Woodsmith Mine is completed. This means that polyhalite can be extracted with minimal impact on the region’s tourism and the North York Moors National Park.
As part of the 2.5 bn € project, BAUER Technologies Ltd., a subsidiary of BAUER Spezialtiefbau GmbH, Schrobenhausen/Germany, has been contracted to build circular diaphragm wall shafts between 60 and 120 m deep (Figure 1). Construction of the diaphragm wall for the service shaft began in December 2017. Among other equipment, three BAUER BC 40 cutters on MC 96 and MC 128 duty-cycle cranes (Figure 2), and three complex BE 500 and BE 550 desanding plants from BAUER MAT Slurry Handling Systems are being used in the project. The bentonite suspension is enriched with a specially developed polymer-based additive to minimize losses into the fractured and porous strata.
Different measurement methods are being combined to produce a clear 3D model of the diaphragm walling works using Building Information Modeling (BIM). This will ensure that the required maximum vertical deviation of 200 mm in 120 m is not exceeded. Once Bauer Technologies has completed the diaphragm shafts, in a follow on operation the production and service shafts will be sunk to a final depth of 1,500 m by a mining company.
Bauer Technologies has made a name for itself in the UK, thanks to the success several extremely complex and technically challenging projects has been involved in. These include specialist foundation engineering works for the redevelopment of the Battersea Power Station in London and work for the important Crossrail infrastructure project.
Further information:
BAUER AG
www.bauer.de