Shaft

North Yorkshire holds one of the largest, high grade polyhalite reserves worldwide. It is located within the North York Moors National Park, ca. 1800m below surface. Once processed, this mineral functions as an organic fertilizer to boost harvest. Sirius Minerals plc are currently developing the infrastructure to mine the polyhalite. This operation requires deep shafts to access the mineral body but also demands an extensive mass transport system (MTS) to keep the impact on the National Park to a minimum. Therefore, at ca. 350m below surface, a series of SCL tunnels link the deep shafts to a conveyor belt system, which again connects the mining operation via a 37km TBM tunnel to its material handling facility.

NATM test tunnel, heavy support Aligning pole (d= 5 cm) should make deformations possible.

The Corsica Street Ventilation Shaft comprises the permanent pressure relief and ventilation adit connecting the down line running tunnel to the shaft and temporary access adit tunnel. The ventilation adit was designed as a permanent sprayed concrete lined tunnel built in two phases: primary and secondary linings. The required watertightness was reached by staggering the joint locations between primary and secondary linings, utilising internal curing agents and steel fibres in the secondary lining sprayed concrete and injecting flexible tubes into joints of the secondary lining.

The Wayside ventilation shaft is one of five needed to provide ventilation and emergency access for the London Tunnels section of the Channel Tunnel Rail Link. The tunnels were designed as permanent sprayed concrete-lined, constructed in two phases, temporary primary and permanent secondary linings. The required watertightness will be achieved by staggering the joint locations between the two linings, utilising internal curing agents and steel fibres in the secondary lining sprayed concrete and using injectable flexible tubes in the joints of the secondary lining.