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In the years leading up to the landslide,
water from the hillside had been a perennial
problem for the people of Aberfan. Starting
in 1949, and possibly earlier, a series of
floods had affected the upper part of the
town, causing damage and disruption, and
leaving a legacy of a ‘slimy black deposit’ in
its wake, which was almost certainly mine
waste. The people of the town repeatedly
wrote to the council and the National Coal
Board asking for this problem to be addressed
to no effect; it is ironic that in the aftermath
of this disaster this flooding issue was solved
through the construction of a simple culvert.
The story of the Aberfan Disaster is seared
into the memories of a generation of people
in South Wales, and it remains a tragedy of
huge proportions. Today, 45 years after the
disaster, there is much to learn from the events
leading up to, and that occurred on, the day.
Prior to the disaster, Aberfan was just another
small, Welsh coal mining village, located in
the valleys of South Wales. Essentially the
reason for the existence of the village lay in
coal mining – it was founded shortly after the
first excavations for the Merthyr Vale Colliery
in 1869. The village was formed primarily of
a close-knit community of miners and their
families, but was sufficiently large to be
able to sustain both a primary and
secondary school.
By 1969, seven tips had been constructed.
Tip 7, from which the disastrous landslide
developed, was started in 1958, and reached
a height of about 40 metres. It contained
about 230,000 m3 of waste. The material was
transported to the tip on trams that were hauled
up an incline by a series of motors, before the
waste was dumped on the tip by a crane.
Pictures from the post-war period show that
the hills above the village were dominated
by a series of enormous spoil heaps. Dealing
with the waste is a perennial problem in coal
mining, which often generates large volumes
of dirty material that has little economic use.
In South Wales, as elsewhere, it was common
to pile the waste close to the mine workings
– in the case of Aberfan on the slopes above
the village.
This area of South Wales has a wet climate
(average rainfall is about 1500 mm per year),
and the hillsides are marked by lines of springs.
The presence of these springs on the hillslopes
above was noted on Ordnance Survey maps
dating from the late 19th Century. Remarkably,
some older tips at Aberfan built on springs or
watercourses had previously failed – for example,
Tip 4 slipped in 1944, and Tip 5 had a large
bulge that was considered to be an indication
that it was unstable. Furthermore, just down
the valley of Abercynon, a landslide developed
in a tip in 1939 that buried a road to a depth of
nearly seven metres. And so, the arguments that
the events at Aberfan were unprecedented, or
could not have been anticipated, cannot
be sustained.
Mining at Aberfan started in 1869; initially
the waste was dumped in tips on the slope
adjacent to the mine. However, as the volume
of material increased, new tips were built on
the slopes higher up the hillside.
The Commission of Enquiry noted that when
coal waste tips are concerned, “water is
undoubtedly the root cause of most failures”.
This was not a new finding – indeed it had
been known for at least 40 years – and 45
years on it is still the case.
The disaster itself occurred on 21st October
1966 at about 9:15am. The day was calm
and sunny at 7:30am, when the team of
men responsible for the dumping of mine
waste on Tip 7 arrived for work. At the top
of Tip 7 they found that it had subsided by
about three metres. The team had to send a
messenger down to report this information to
the mine managers as the telephone was out
of action as a result of the repeated theft of
the cable. A decision was taken by the mine
managers to cease tipping at that location,
and an additional team was sent up to move
the tipping infrastructure back from the
area of active movement. By the time they
reached the top, the subsidence had further
developed, with another three metres of
movement being reported.
The final, catastrophic collapse developed
apparently spontaneously as an initially
rotational movement that rapidly transitioned
into a flow. About 107,000m3 of material
flowed down the hillside and into the village.
Descriptions of the event from eye-witnesses
bring home the suddenness and catastrophic
nature of the landslide. Most witnesses
report a noise that sounded like a jet plane
passing low over the village; the witnesses
also describe a wave of debris, higher than
a house, moving fast and demolishing houses
‘like a pile of dominoes’. The landslide
behaved like a liquid, but with twice the
density of water, sufficient to demolish
everything in its path. Some victims who
escaped the main flow were struck and
injured by flying debris.
By the time the landslide stopped, it had
demolished Pantglas Junior School and
18 houses, and had seriously damaged
the secondary school and many more
houses. A total of 144 people were killed,
including 116 children. CONTINUED >