About 12.30 pm on Saturday 19th March, 1988, mining operations in the St. Aidan’s Open Cast coalmine broke the banks of the River Aire and water flooded into the void caused by the open-cast mining. A 300ft breach resulted and water from the River Aire poured 200 ft down into the workings – a massive waterfall.

The water level between the mine and the river was not reached until the Tuesday and by this time a 200ft deep, 190 acre lake had been created, covering 2 million tonnes of coal. On the Sunday, March 20th, the river lost pressure (because of the outfall) in its downward flow and the River Calder flowed upstream from Castleford.

The site was evacuated on Saturday the 19th without loss of life or limb, or machinery. At its level with the river, the site contained 4 billion gallons of water, with a maximum depth of 70 metres. The position of the Lemonroyd Lock houses was very precarious. There were fears of pressure causing a canal breach as there was only 25 metres between the River Aire and the canal banks.

Lemonroyd Lock houses were evacuated on the Saturday night but the residents returned on the Sunday. The bank was temporarily reinforced by stone revetments in cooperation with the Yorkshire Water Authority.