Keltbray to deliver a £12m extension to its current C1 Shaft contract regarding the HS2 Align joint venture.
In this project, the first two ventilation shafts are to be built in August at Chalfont St Peter and Chalfont St Giles.
The contract includes internal shaft construction works to build slip-formed concrete cores and lining walls, to create a collar structure to enable the TBMs to pass through the base of the shaft and reinforced concrete works at the base of the shafts.
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