22-Nov-2018
Chesham Road Vent Shaft
(Provisional schedule, Nov 2018
Reconstructed from Phone image)
| Main Activities | Indicative Timescales | Current Dates |
| Site Setup | 4 months | July 2021 |
| Ground Treatment (Dissolution Feature) | 1 month | November 2021 |
| Shaft (D-wall) construction | 4.5months - extended hrs | December 2021 |
| Main Earthworks Excavation | 1.5 months | April 2022 |
| Access construction, shaft base slab and tunnell boring machine reception | 4.5 months | June 2022 |
| Construction of pressure relief adit | 10 months | October 2022 |
| Arrival of TBMs through shaft | 3 months | August 2023 |
| Shaft lining, internal structures | 13 months | November 2023 |
| Construction of Headhouse | 12 months | October 2024 |
| Estimated total time | 52 months |
Entries shown in bold will generate the most lorry movements. The shaft construction timescale assumes concrete pouring continuously for 12 hr shifts. This requires an exemption from standard working hours.