By William Ollerenshaw in c.1889, who later became the Manager of Denton Colliery

The above report suggests that there were two inclined planes. The lower incline was used to remove coal from the coal face in the Black Mine and transport it to the bottom of the engine brow (inclined plane) and when the coal had been winched up this it was at the pit bottom, that is, at the bottom of the winding shaft.

Around the time that this report was made there was an explosion at Hyde Lane Pit that resulted in fatalities. The death roll was 23 men and boys. The explosion occurred on the 18 January 1889.

Longwall Method of Coal Working
With reference to the simplified plan of a coal mine shown blow, the upcast shaft (fowl air drawn out) and downcast shaft (fresh air drawn in) are shown in the centre, marked U and D respectively, and these are surrounded by uncut coal. The downcast shaft is also the winding shaft. Galleries radiate from the shafts and the roofs of these are supported by pit props. The grey areas have been shut (abandoned) and these are the 'gobs'†. Here, all the coal has been removed and the roof is allowed to settle down gradually. In the 19th century, each coal face or wall was about 100 yards long and this is where coal was being hewed and then carried to the surface. As the coal was removed, waste stone was used to build drystone walls that were typically from 6 to 20 feet wide and these were arranged in parallel lines at right angles to the advancing coal face or wall. The purpose of these was to support the roof after the coal had been removed. As the coal face advanced, the underground railway system for carrying coal away was constantly being rearranged and increased in length.

†Depending upon the district, the words 'gob' and 'goaf' can both refer to the same thing, namely the void left after coal has been extracted. The word 'gob' can also refer to waste material separated underground.

A disadvantage of longwall working was that more gas could be released from a coal seam depending upon its volatility. When the gas released was firedamp (methane) then there was an increased risk of an explosion.

Following such an explosion, a toxic mixture of gases could be left which itself could cause a much larger explosion of coal dust. Afterdamp consists of carbon dioxide, carbon monoxide and nitrogen. Additionally, hydrogen sulphide, a highly toxic gas, could also be present. Nevertheless, it is usually the high content of carbon monoxide which is fatal by depriving victims of oxygen by combining with haemoglobin in the blood.

Afterdamp was the lethal gas which caused many casualties in the pit disasters of the British coalfields.

At just after 9:00am on the Friday, 18 January 1889, an underground explosion occurred at Hyde Lane Colliery that caused 23 miners to be killed and another five to be seriously injured.

Longwall Method of Coal Working.

U = upcast shaft (foul air drawn out)
D = downcast shaft (fresh air drawn in)
Circulation of fresh air underground was controlled by a system of doors and ducts that are not shown for clarity.

Acknowledgement
  Acknowledgement and thanks are due to A Etchells.