Whitby Mine Shaft Construction Continues with Drill and Blast Process

Thursday, 10 February 2022 06:15

By Matthew Pells

The latest stage of sinking the shafts at Whitby's Woodsmith mine involves using explosives to loosen the rock.

In addition to the two main shafts, a 360 metre deep shaft is currently being constructed at the mine site from which a tunnel boring machine (TBM) will be launched to support the construction of the mineral transport system (MTS). The first TBM has already set off from the Wilton end of the tunnel and has already reached 17km.

The first 115 metres of the MTS shaft has already been sunk using a vertical shaft sinking machine – a world record depth for this equipment.

The next phase of shaft sinking will involve a conventional ‘drill and blast’ process.

Matt Parsons from Anglo American says the underground blasts will help get the shafts to the next level and wont be noticeable from the ground.

Blasting started on January 25th and will take place between the hours of 7am and 7pm. Anglo American say there will be no more than one blast a day.

The company say they have contacted every household within a 1.5km radius of the shaft and invited them to be notified – via email and text message – of blasting activity 30 minutes before it takes place.

The process of deepening the mine shafts involves installing a "Galloway" within the temporary winder tower. A Galloway is a suspended, multi-decked working platform which will be suspended in the shaft and secured with winches.

From the Galloway blastholes are then drilled and filled with explosives. Before each round is blasted, the Galloway is raised from the bottom of the shaft by 30 metres and approximately three metres of material is then ‘blasted’.

A mucker on the Galloway loads the excavated material into a muck skip before hoisting it to surface where water is separated out.

The 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, which is expected to take approximately nine months to complete. One blast will occur approximately every 24–48 hours.

The work is part of the ongoing construction at Whitby's Woodsmith mine which will see around half a billion pounds of investment this year.

Anglo American says that as well as working on deepening the main shafts they are also continuing the progress of the tunnel to Teesside, which will carry the mined potash to the port.

Matt Parsons says the tunnel work is going well.