With the two broken water mains still pumping water into the spoil in Aberfan, the slip continued to move through the village, and it was not until 11:30 am that the water authorities managed to turn off the supply. It was estimated that the mains added between of water to the spoil slurry. With movement in the upper slopes still a danger, at 12:00 noon NCB engineers began digging a drainage channel, with the aim of stabilising the tip. It took two hours to reroute the water to a safer place, from where it was diverted into an existing water course.