|Because of the coal and ironstone mining of the North
Staffordshire deposits which lie under Stoke-on-Trent there have been incidents
of buildings sinking many feet and also holes opening up in the fields and
Not only this but the whole city is sinking..... by using
satellite imaging it was showed that over a 2½ year period between 1993 and 1995
a large portion of Stoke-on-Trent sank by up to 80mm - this is the equivalent of
the effect of a major earthquake!
The Etruria Works on
the Trent & Mersey canal - 1898
The same works -
Wedgwood's Etruria factory
The two photos should be compared - by the 1930's
there is now a railing alongside the canal footpath and a slope down
to the factory frontage.
on subsidence of Wedgwood
Subsidence in Stoke-on-Trent
1844 court case on
owned coal mines which extended under, among many other areas, Shelton. When
mining for coal supports were left to try to prevent collapse of the mine.
Granville stared to mine for iron-ore. The method and economics of iron-ore
mining meant that no support was left and consequently large scale damage
was done to houses above some of the workings.
In 1844 a Mr.
Hilton, who lived in Union Street, Shelton, brought an action for
compensation (he was supported by others in the same predicament) against
admitted that his mine works had caused the damage.
on the 1844
16th June 1857 -
Staffordshire Advertiser newspaper.
of a coal mine:
A singular and fatal casualty occurred on Monday afternoon,
at a colliery at Cobridge, on the estate of the Misses
Adams, by a portion of the bottom of a fish pond giving way,
consequent on the mining operations being carried on too
near the surface.
Immediately under the fish pond are some old workings which
events have disclosed had been worked up to within about
five feet of the bottom of the pond, and where a man was
employed that morning in getting ironstone.... Mr Tinsley
(who, with Mr Samuel Fox, rented the mine) was drowned, his
body being discovered about an hour after the accident...."
Note: there were 11 men and
boys in the pit at the time, working on two levels. Mr
Tinsley was one of 3 on the lower level, only 11 yeards from
the bottom of the shaft.
differential interferogram of Stoke-on-Trent
- over a 2½ year period -
interferogram is overlaid over a satellite image of the area
The fringes represent
recent ground movement over a period of almost 2½ years, during the
years 1993 to 1995.
8 cm subsidence over
Over this period, the satellite survey found that the centre of
Stoke-on-Trent sank by about 8 cm. The subsidence extending for 5 km
(East-West) and 10 km (North-South).
We do not have to look very far for a
reason for this ground displacement. Subsidence over underground
coal workings has long caused problems in the conurbation, although
there is no complete survey of the hundreds of workings.
There is an unusually thick sequence of
Coal Measures in the region, with 52 individual seams from 1cm to
3.5m thick occurring over 1100m of rock succession dipping gently
beneath the conurbation in a deep trough.
By superimposing the fringe contours over the
geology map of the area, it was noted that 30 of the 52 coal seams
occupy the fringe core. These seams trend north-northwest, exactly
parallel to the strike of the core of fringe pattern. This "grain" is
shared by the strike of the geological strata, the topography (there is
a height range of 80m to 100m across the core of the fringes) and the
trend of minor landslips, along steeper slopes where harder sandstone
outcrop. These landslips, the largest about 1km long and 150m wide, are
nowhere large enough or consistent enough to result in displacement
adequate to yield a fringe.
The stacked coal seams reach the surface to
the east of, and within, the core of the fringes. They dip westward,
mostly consistently, at 10° to 20°, beneath the core of the fringes. The
generalised sub-surface distribution of these seams in the geological
section shows a coincidence of stacked seams and the fringes that is so
strong that this is unambiguous, if circumstantial, evidence for
subsidence of the coal workings.
There are an estimated 8000 disused shafts in the Stoke-on-Trent
conurbation and at least 200 abandoned adits within the area defined
by the fringe patterns. There are almost no active coal workings in
the area and none whatsoever within the fringe core. There is a very
close coincidence of the fringe contours and the outline of the
areas of all underground coal workings and, displaced updip (that is
to the east), the area of mine workings within 30m of the surface.
Many of these workings are ancient and predate systematic survey and
recording. As there are only piecemeal survey of these workings,
sudden unexpected collapse
over mining voids or over areas
where the pillars of the old seams, or the mouths of shafts
collapse, are a feature of the whole conurbation.
demonstrated is at relatively shallow depths, probably no more than 100m
and maybe no more than 30m depth. Extensive underground shafts,
"bell-pits", adits and workings, many by pillar and stall (in which
pillars of coal are left standing, usually on a rectangular grid to
support the workings) underlie the whole conurbation. Mining has been
almost totally abandoned, and collapse of roof supports and pillars in
particular, and seasonal water logging is causing subsidence.