The Brunel Engine House - the Miner's Life Exhibition

The Work


The Shield

The problem that had defeated previous attempts to tunnel under the Thames was the soft sediment under the river. Marc Brunel's success followed his invention of the 'tunnelling shield', which supported both the tunnel-face and the roof of the tunnel, and enabled bricklayers to work just behind the advancing shield.

It was a metal apparatus big enough to be manned by 18 miners. Each miner occupied a separate 'cell'. The face of the tunnel, which would have been semi-liquid was supported with elm boards, 3 foot long x 6 inches deep x 3 inches deep (0.9m x 0.15 x 0.075m). Each board was separately supported by screw jacks bearing against the wall of the appropriate cell.


The Shield


Detail of Screw Jacks and Elm Boards

(there were 12 horizontal elmboards per cell)

At the start of a shift the miner unscrewed the top board, and started to remove the 'spoil', sometimes with a pick-axe, if it was hard, or even sometimes with bare hands, which was found to be the most efficient way of dealing with the semi-liquid substance. After removing a set amount of spoil, perhaps six inches to a foot, the elm board was replaced and supported by the screw jacks. The next board down was removed and the process repeated removing each board at a time. In this way, only a horizontal 6 in. section of the tunnel was unsupported minimising the risk of inundation.

In addition, each 'cell' moved independently, depending on how fast the occupying miner could work, and on the quality of the earth behind the boards. This provided a flexible and relatively safe way to work.



Email the Museum. Page Last Updated on 20 April 2002. Designed by Kevin Flude of Cultural Heritage Resouces