Archive - Wednesday, 17 July 2002
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Radstock's coal mining history
THE Radstock area is well known for its association with coal mining, with the last pit closing in the 1970s. The coalfield was very small, its surface outcrop extended from just north of the Mendip Hills.
Although the surface outcrops are restricted, the coal-bearing rocks were found over a wider area beneath a cover of younger rocks.
The first references to coal working in Somerset are from the 16th century; at the mining peak 79 separate collieries were listed.
At this time the annual output of coal from Somerset was 100,000 tons, increasing to 1,250,000 tons by the early 20th century.
But with the rise of industrialisation in the Midlands and North of England, the industry began to decline and production ceased in the 1970s.
There is still plenty of workable coal beneath north Somerset and no doubt one day it will be re-discovered.
The coal around the Radstock area was laid down in the carboniferous period, some 345 million years ago.
Coal is an unusual rock as it contains no minerals at all, but is composed of the decayed remains of plants which are solidified into a few substances called 'macerals'.
These include material from the coarse cellular tissues, which look like charcoal and gives coal its 'sootiness'.
Coal seams are often not very thick, maybe a metre from top to bottom, but this represents a considerable amount of plant debris and elapsed time where no other rocks would have been laid down on what once would have been swamp land.
Many of the rocks of the upper carboniferous period are very soft and have weathered quickly, leaving rocks laid down before them exposed.
Few of these rocks are now visible at the surface and we need to rely on diggings made by man to see them.
Apart from the rare natural outcrops, we rely on the waste tips from past mines to see these rocks.
Waste tips from old coal mines are the most obvious reminders of the mining period and look curiously out of place today, resembling small volcanoes like the one close to Midsomer Norton.
Unfortunately, these spoil tips are normally too weathered to yield large lumps of rock which might contain fragments of plant and insect fossils.
Yet a preserved area near Writhlington has revealed many well-preserved fossils of cockroaches, grasshoppers, dragonflies and spiders.