MTS Shaft sinking

The tunnel boring machine starting at the mine site requires a shaft to be constructed, down which the TBM components will be lowered and assembled in a cavern at the bottom. An access shaft is also required at Lockwood Beck to facilitate refurbishment of the Wilton TBM, before it continues south.

The majority of the mineral transport system shaft sinking operations will be undertaken by traditional drill and blast methods, using a multi-decked working platform (called a Galloway) suspended on winches from the surface. However, first the upper sections of the shafts must be sunk through near surface aquifers and sealed.

At Lockwood Beck, this is achieved by injecting grout into the ground around the shaft to create a grout curtain, then digging out and lining the shaft with concrete. When at around 50m depth, the Galloway can be launched.

Vertical Shaft Sinking Machine

At Woodsmith Mine, because of a deeper aquifer, a specialist Vertical Shaft Sinking Machine was chosen. The machine is designed to work underwater with a shaft lining being lowered behind.

The machine reached a depth of 115.2m in May 2019, setting a new world record for this type of excavation in the process - the previous record was 84m - testament to the groundbreaking, innovative approach that we have taken to construct our Project.

Read more about our record breaking Vertical Shaft Sinking Machine here.

Galloway shaft sinking

Once the shafts have reached the required depth, the shaft is excavated to -360m with the Galloway in the following process:

  • Blastholes are drilled then filled with explosives.
  • Before each round is blasted, the Galloway is raised from the bottom of the shaft by 30 metres.
  • Approximately 3 metres of material is then ‘blasted’.
  • A mucker on the Galloway loads the excavated material into a muck skip before hoisting it to surface
  • A concrete shaft lining is installed at the end of every second drill blast cycle.
  • The process is repeated until the shaft has reached its full depth

The first Galloway was lowered into the MTS shaft at Woodsmith Mine in July 2019: