Table showing the explosions and inundations, with the date and number of lives lost, since the beginning of 1869, in Durham, brought down to the end of 1906, with two statements on the dust theory by Mr J. Forman.

A THEORY SHOWING HOW COAL DUST IS IGNITED AND EXPLODED IN A COAL MINE, MORE ESPECIALLY ON IN-TAKE AIR ROADS

In the first place, there must be a considerable quantity of very fine and dry coal dust in the immediate proximity of a shot when fired; and if the shot is a strong one the concussion will be very great.

This force, acting on the air, throws the finest particles of coal dust into the circulating current, in a finely divided state, with orbid motion, thereby causing each particle of coal dust to be surrounded with air, and these particles of dust in this condition coming in contact with the flame of a shot, are easily ignited.

At the moment of ignition the temperature of the particles of dust is low, but as the ignition extends to other particles, and they become ignited in quantity, the temperature rises, so that the motion of the heated particles becomes more rapid by expanding and compressing the air, until their velocity is so great that the temperature of the burning dust is raised to the temperature of gas flame, exploding the coal dust in its course.

At this high temperature, the expansion of the air will develop great force, which acting on the dust at rest, will whirl it into the air current, and this will be continued so long as there is a sufficient quantity of coal dust and air to feed the flame.

John Forman.

To J. Wilson, Esq.,
Secretary to the Royal Commission on
Explosions from Coal Dust in Mines.

Dear Sir,—In October 1871 an explosion occurred at Seaham Colliery, and my attention was called to it; and, after considering all the circumstances of the case, I eventually came to the conclusion that the shot fired by the two Simpsons ignited the coal dust and caused the explosion.

In September 1880 another explosion took place at Seaham Colliery. I went down the pit in the evening of the day of the explosion with Mr Stratton (the manager) and other Mining Engineers, and I remained at Seaham Colliery for 12 months, until the last body was found, and was, during that time, down the pit almost every day as an explorer. I also attended the inquest and gave evidence. I was satisfied from what I saw that the shot fired by Simpson and Brown ignited the coal dust and caused the explosion.

In February 1882 an explosion occurred at Trimdon Grange Colliery. I went down the pit and attended the inquest, and from what I saw and heard I concluded that the explosion was caused by a flushed kitty or straw at Maitland's shot firing a small quantity of fire-damp, which ignited the coal dust and caused the explosion.

In April 1882 an explosion occurred at West Stanley Colliery. I attended the inquest, and from what I could learn the shot fired by the two men (Douglas and Hutchinson) ignited a small portion of fire-damp, which fired the coal dust, and brought on an explosion.

In March 1885 an explosion happened at Usworth Colliery. I attended the inquest, and came to an opinion that the shot fired by the two men, named Brown, ignited the coal dust, which produced an explosion.

In December 1886 an explosion occurred at Elemore Colliery. I went down the pit and attended the inquest. I was satisfied, in my mind, that the shot fired by the three men (Johnson, Appleby and Luke) ignited the coal dust, thereby causing the explosion.—Yours, etc.

John Forman.

December 1886.