The Aberfan Landslide illustrated the mining industry’s lack of knowledge concerning the mountains of waste they were generating, and the government’s lack of oversight of the mining industry.
The Merthyr Vale Colliery had been dumping mining tip onto the mountainside above Aberfan for 90 years without any surveying, or heed to the well-known and marked springs and streams underneath the tips. Previous small slides of Tip #7, averaging 3 to 6 meters, had been noted, but had not triggered concern. Dumping of additional waste onto the tips was conducted randomly, with no surveying or engineering oversight for stability.
Heavy rainfall for two days saturated Tip #7, exacerbating the existing undercutting and lubricating of the pile by streams running through the Brithdir sandstone underneath the tip. The resulting 150,000 cubic meters of slurry ran towards town at the unexpected rate of 20 km/hour, precluding any warning despite eyewitnesses.
Britain passed the Mines And Quarries Tips Act in 1969 to regulate the mining industry’s waste management and broaden their responsibility. Modern studies in hydrodynamics and waste management ensure more thorough handling of mining waste, and safer placement away from communities.