Mainsforth Colliery

Miscellaneous Notes and Incidents

The overwinding accident occurred at Mainsforth Colliery, Durham. Twenty persons were being lowered and one raised. When the descending cage reached a point five revolutions from the bottom, the engineman decided to retard the motion of the engine by putting steam power against it. He pulled over the reversing lever, but unfortunately did not securely notch it. On opening the steam throttle, the unsecured reversing lever dropped back into the normal running position. In the meantime the last overspeed control trip, 60 feet from the end of the wind, had been passed. The overwinding apparatus came into operation but the descending cage bumped on the landing baulks and the ascending cage was detached. Twelve of the occupants of the descending cage were slightly injured and a workman at the surface sustained a bruised shoulder when struck by the shaft-top gate which was dislodged from its guides.

With a view to averting a similar accident a "slow-banking" device was fitted to the overwind preventer to provide continuous control, or "shadowing," throughout the last few drum revolutions in the wind.

Source: 1935 Mines Inspectors Report