Marine Colliery explosion, 1927

An underground gas and coal-dust explosion in the Black Vein seam at Marine Colliery killed around 52 men in the early hours of 1 March 1927, one of the major South Wales colliery disasters of the interwar period.

Cause

The official Inspector of Mines report (Mr Henry Walker) concluded an explosive firedamp/air mixture at the 'C' face was ignited either by stones falling on stones already fallen, or at the bare glowing filament of an electric lamp, with coal dust amplifying the blast; the precise ignition source was never conclusively established.

What happened

The explosion occurred at 12:50am on 1 March 1927 at the Black Vein seam's 'C' face, roughly 350 yards down and about 1½ miles from the shaft on the eastern side of the workings. Colliery manager Edward Gay ordered the ventilation fan speed reduced, credited with slowing the spread of flame and limiting further fatalities.

Rescue & recovery

Manager Edward Gay reached the pit at 1:05am and the Crumlin Rescue Station was alerted; rescue parties made repeated descents over several days, recovering all bodies by 11 March 1927.

Investigation & inquiry

An inquest was held by coroner W. R. Dauncey at Tredegar Town Hall, running from 12 July to 3 August 1927 and hearing evidence from 79 witnesses; the jury returned a verdict of accidental death and recommended safety improvements including mandatory pre-shift searches and enhanced examiners' reporting.

Memorials & commemoration

A memorial tablet to the 41 of the 52 dead who were Cwm residents was unveiled at the Cwm Institute on 29 September 1927.

What's uncertain

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

• Reported predominantly as 52 men killed (NMRS disaster page, welshcoalmines.co.uk); an NMRS overview page separately gives 51 — kept as an unresolved minor discrepancy rather than silently rounded. (uncertain) ^1,2

Recorded claims

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

• Reported predominantly as 52 men killed (NMRS disaster page, welshcoalmines.co.uk); an NMRS overview page separately gives 51 — kept as an unresolved minor discrepancy rather than silently rounded. (uncertain) ^1,2
• Colliery manager Edward Gay's decision to reduce ventilation fan speed after the explosion is credited with slowing the spread of flame and limiting further fatalities. ²

Related terminology

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

• Coal (contextual relationship)
  Named in this record’s cause: “…fallen, or at the bare glowing filament of an electric lamp, with coal dust amplifying the blast; the precise ignition source was never…”
• Colliery (contextual relationship)
  Named 3 times in this record, first in the summary: “…gas and coal-dust explosion in the Black Vein seam at Marine Colliery killed around 52 men in the early hours of 1 March 1927, one of the…”
• Firedamp (contextual relationship)
  Named in this record’s cause: “…Inspector of Mines report (Mr Henry Walker) concluded an explosive firedamp/air mixture at the 'C' face was ignited either by stones falling on…”
• HM Chief Inspector of Mines (contextual relationship)
  Named in this record’s cause: “The official Inspector of Mines report (Mr Henry Walker) concluded an explosive firedamp/air mixture…”
• Shaft (contextual relationship)
  Named in this record’s narrative: “…seam's 'C' face, roughly 350 yards down and about 1½ miles from the shaft on the eastern side of the workings. Colliery manager Edward Gay…”

Sources

1. (secondary) Marine Colliery Explosion — Cwm — 1927 — Northern Mine Research Society
2. (secondary) Marine Colliery, Cwm — welshcoalmines.co.uk

Record created: 26 August 2026 · Last researched: 26 August 2026