A Welsh Coal Mines web page

Killan Colliery.

There were two drifts, which formed the Killan colliery, the Penlan and the Penclawdd. The Killan Colliery Company opened the first of which in 1899.
In 1908 the mine was owned by Homes and co. and employed 344 men at Penclawdd and 117 at Penlan.
In 1918 the mine employed 654 men mostly from the village of Dunvant and the local area. Killan colliery was supplying fuel to the Grovesend Steel and tinplate works in 1924 and was part of the Fuller group. By this time one of the drifts was 1,500 yards long.

From a list 1923, there were 384 men employed, producing House coal from the Penclawdd seam.

On 27th of November 1924 an inrush of water occurred between the number 1 and the Penlan vein, the water broke in with a terrible force ripping out roof supports and sweeping everything away in its wake.
When the news got to the surface rescuers rushed to assist the survivors out of the mine. Two bodies were recovered almost straight away. It soon became apparent that some of the men were entombed in the mine and pumps had to be brought in from nearby collieries. After some time it was discovered that 11 men were trapped deep below ground.
For the next 50 hours frantic attempts were made to reach the trapped miners. Then a call came up from below ground calling for ladders to be sent into the mine. Some of the men had been located and were soon on their way out from the pit after 50 hours underground breathing the air contained within an air pocket.

Three men remained missing, trapped somewhere in the far reaches of the mine. Divers were brought in to search for the men below the water level but to no avail.
It wasn't until New Years Day, 1925 when the bodies of the three unfortunate men were recovered.
The miners who lost their lives were;

To add to this very sad episode one of the rescuers, a fireman Thomas William who worked at the Elms Colliery was killed on the railway line going home after dark. His decapitated body and severed head being found on the line in the morning. The mine was closed a little later in 1925.