Grassmoor Colliery Sinking Accident, 1856

On 13 December 1856 two men were killed sinking a new shaft at Grassmoor Colliery, in Derbyshire, when a mass of earth near the shaft top slipped away without warning and carried the timbering down on them.

Cause

A mass of earth near the top of the sinking shaft, loosened where two slip faults intersected and after a hard frost followed by thaw and rain, slipped suddenly and carried the temporary timberwork before it.

What happened

J. Bradley, aged 60, and W. Fletcher, aged 25, were killed. The shaft was only seventeen yards down, secured temporarily with timber until a foundation could be found for brickwork. As the bricking was in progress a mass of earth near the top slipped without warning from both sides of the pit and carried the timberwork down. The Inspector, John Hedley, found the cause plain afterwards: two slip faults intersected in the shaft five or six yards from the surface, and the tender strata, loosened by a hard frost and sudden thaw, had parted from their bed; the wet, loose ground during sinking had hidden the faults.

Sources

1. (primary) Grassmoor Colliery shaft accident, 13 December 1856 (from the 1856 Mines Inspector's Report, John Hedley) — Durham Mining Museum
2. (secondary) Durham Mining Museum: Grassmoor Colliery — Durham Mining Museum

Record created: 9 September 2026 · Last researched: 22 September 2026