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Mine Gases


Les Havill
Mine Gases

Simon and Waynes Havill wearing a smoke helmet. Because air was pumped into the helmet the wearer could only travel about 200 meters.

Les Havill, Fire Officer at Calverton examining his flame for gasses.



Simon and Waynes Havill

During the normal working of coal seams it is necessary to pass through the workings a sufficient quantity of air to keep the atmosphere properly conditioned for breathing, because of the fact that firedamp is slowly exuded by the coal and surrounding strata, and carbon dioxide gas is formed by oxidation of the coal and timber and by the breathing of men and animals. The latter processes remove oxygen from the mine atmosphere and thereby tend to bring the percentage below the normal 21%.

Firedamp. Methane(CH4) Blackdamp or Stythe.
Carbon Dioxide (C02). Carbon monoxide. Hydrogen Sulphide.
Nitrogen. Mine Gases  
There are two methods by which CO may be readily detected in mines.

Detection of Carbon Monoxide.

(1) By using a small bird such as a canary. This method depends on the fact that the small volume of blood in a bird becomes saturated in much less time than does the greater quantity in a man. It is therefore possible to detect signs of CO poisoning in a bird before the observer himself experiences dangerous symptoms. However, the safety factor becomes less and less as the percentage of CO approaches one. To make the test the bird is carried in a small cage at arms length in front of the observer, so that it is under constant observation. The first sign observed in the bird is loss of the sense of judgement, seen when the bird fails to connect the perch when hopping on to it. This condition develops in a few minutes in an atmosphere containing 0.1%CO.

Pete Barton (Dick ), a full-time brigadesman from Chesterfield Rescue Station,

Pete Barton (Dick ), a full-time brigadesman from Chesterfield Rescue Station, 1980

When a higher concentration is suddenly encountered it is indicated by the bird losing the power of its legs, and collapsing prostrate on the cage floor with its wings out spread.

No person should ever attempt to make this test unless previously he has had the opportunity of observing the behaviour of a bird when subjected to various concentrations of carbon monoxide under laboratory conditions.

(2) By means of a chemical substance. The "Hoolamite" detector makes use of a colour change brought about by the action of carbon monoxide on iodine pentoxide.

It consists of a small glass tube filled with pumice stone which is impregnated with a catalyst and a mixture of iodine pentoxide and fuming sulphuric acid. On making the test a given volume of air is passed through the tube by means of a syringe, when the presence of CO is indicated by the contents of the tube changing colour from grey to green. The intensity of the tone of the green colouration is then compared with a standard colour scale tube to determine the actual percentage present.

When the conditions are wholly unknown, say immediately after a firedamp explosion, it is the best procedure to make a preliminary test using a small bird.

Accurate determinations are made by collecting air samples, 500 cubic centimetres, for analysis by the Graham Lawrence method.