viewer, Mr Thomas Forster. He confirmed much that had earlier been reported; the pit was well ventilated and Davy lamps were in use. The seat of the explosion was found by Mr Foster to be an underground engine used to haul coals to the pit base. The engineman had added fresh coal to the fire and closed the damper before going off shift at 16:00. The damper should have remained slightly open to allow burnt gas from the fire to escape up the chimney. It was supposed that the damper had been closed fully and partial combustion had occurred effectively generating town gas ("acting as a retort"). The gas eventually escaped and the resultant explosion caused major damage to the boiler and flue. Four viewers from other pits all corroborated Foster's conclusions. The engineman, George Hope, said that he put on around 3½ pecks of small coals and "left the damper open about an inch and three-quarters I always leave my fire this way". The coroner's jury returned a verdict of "Accidental Death". The jury recommended that a pin was placed in the damper so stop it closing to less than four inches (). The memorial to 1812 A memorial to the 91 victims was placed in St Mary's Churchyard where most of the coffins were placed in a common grave. The monument has a square base with a square pyramid above. On each of the four faces is a brass plaque: References Footnotes Citations Bibliography External links Pictures of the memorial on the Durham Mining Museum website: General view of the monument Brass number 1 Brass number 2 Brass number 3 Brass number 4 See also Mining accident Mine safety Coal mining disasters in England History of County Durham 1812 in England 1813 in England 1821 in England 1847 in England 19th century in County Durham 1812 mining disasters 1813 mining disasters 1821 mining disasters 1847 mining disasters 1812 disasters in the United Kingdom 1813 disasters in the United Kingdom 1821 disasters in the United Kingdom 1847 disasters in the United Kingdom