Monday, August 09, 2010

Bus in a Hole

1988 - A surprise stop for the passengers of the number 26.
No-one was hurt.

Perhaps I should not have mentioned the other day that geologically Norfolk is predominantly composed of chalk, (Aug 7th post) because a new hole has now appeared in a Norwich road some 9 feet deep! Memories from 1988 when a double-Decker bus fell into a hole have now resurfaced. This world-famous image of an extraordinary event is well worth seeing again aS visible proof that living in Norwich can sometimes be exciting!

Norwich in fact  is renowned for having subsidence problems. Not only does it have many chalk mines, but also a network of tunnels underneath its streets and buildings, including more undercrofts than any other UK city.

It's possible that the chalk mines of Norwich date from as early as the 11th Century. Chalk was mined underneath the City and extracted in great quantities to burn into lime for mortar. Flint was also mined and used as stone for building. Mining tunnels known to exist under medieval Norwich can be found between 12 and 90 feet under the surface . They vary in size from 6 to 16 feet in height and from 6 to 12 feet in width . These tunnels and mines are often arranged in a grid-like pattern. City engineers have to regularly inspect these tunnels in order to determine their condition and to prevent any further collapses.

The most investigated system of these tunnels is a 1600-feet-square grid maze of tunnels beneath Earlham Road. It was re-discovered in 1823; coloured lights were fitted and some of the large passageways were given attractive names such as Beehive Lane, Bacchus Street and Royal Arch. They were once a popular attraction for tourists and local courting couples to wander through.

A full history and record of the extensive underground passages, undercrofts and mines in Norwich has yet to be written.

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