Dillwyn Colliery gas asphyxiation, 1958

Two men were suffocated by gas in No. 1 Pit of Dillwyn Colliery, Seven Sisters, on 29 December 1958; the fireman, Kenneth Davies, who died trying to help, was awarded the Edward Medal posthumously.

Cause

An accumulation of gas that suffocated men walking through the workings.

What happened

On 29 December 1958 a group of men walking together in No. 1 Pit at Dillwyn were overcome by gas they could neither see nor smell. One survivor, Kenneth Williams, said that a young assistant repairer was walking about twenty yards ahead when he himself felt dizzy and began reeling, someone shouted that something was wrong, and he fell; he managed to stagger some three hundred yards to raise help. The assistant repairer and the fireman, Kenneth Davies, a married man with two children, the younger five weeks old, both died. Davies was awarded the Edward Medal after his death, and four other men received the Queen's Commendation for Brave Conduct.

Rescue & recovery

The fireman Kenneth Davies died going to help; four other men received the Queen's Commendation for Brave Conduct.

What's uncertain

Points where sources disagree or the record could not be settled; both accounts are kept. All open questions in the archive.

• The second man is named Peter Segadelli, 20, by Welsh Coal Mines and P. Jaundells by NMRS. (disputed) ^1,3

Recorded claims

Individual factual claims, each attached to the source(s) that support it below. Where sources disagree, both are kept.

• Two men were suffocated by gas in No. 1 Pit, Dillwyn, on 29 December 1958. ^1,2,3
• The fireman Kenneth Davies was posthumously awarded the Edward Medal and four others received the Queen's Commendation for Brave Conduct. ¹
• The men were overcome without warning by gas they could not see or smell; one survivor staggered about 300 yards to raise help. ¹
• The second man is named Peter Segadelli, 20, by Welsh Coal Mines and P. Jaundells by NMRS. (disputed) ^1,3

Related terminology

Mining terms this disaster is structurally linked to, with the nature of the relationship.

• Colliery (contextual relationship)
  Named in this record’s summary: “Two men were suffocated by gas in No. 1 Pit of Dillwyn Colliery, Seven Sisters, on 29 December 1958; the fireman, Kenneth Davies,…”
• Fireman (contextual relationship)
  Named 3 times in this record, first in the summary: “…1 Pit of Dillwyn Colliery, Seven Sisters, on 29 December 1958; the fireman, Kenneth Davies, who died trying to help, was awarded the Edward…”

Sources

1. (secondary) Welsh Coal Mines: fatalities 1958 — Welsh Coal Mines
2. (primary) NMRS Coal Mining Accidents and Deaths: K. Davies, Dillwyn No.1, 29 December 1958 — Northern Mine Research Society
3. (primary) NMRS Coal Mining Accidents and Deaths: P. Jaundells, Dillwyn No.1, 29 December 1958 — Northern Mine Research Society

Record created: 16 October 2026 · Last researched: 16 October 2026