Reasons for Designation
Coal has been mined in England since Roman times, and between 8,000 and 10,000
coal industry sites of all dates up to the collieries of post-war
nationalisation are estimated to survive in England. Three hundred and four
coal industry sites, representing approximately 3% of the estimated national
archaeological resource for the industry have been identified as being of
national importance. This selection, compiled and assessed through a
comprehensive survey of the coal industry, is designed to represent the
industry's chronological depth, technological breadth and regional diversity.
Coalmills are water-powered pumping installations, generally consisting of a
series of waterwheels set in a vertical sequence which were employed to drain
single mines or areas of mine workings. They were developed towards the end of
the 16th century in response to the increased need for mechanical mine
drainage arising from the development of large-scale coal mining. They were
established primarily in the north eastern coalfields during the 17th and
early 18th centuries, although further examples are thought to have existed
elsewhere. Coalmills survive almost exclusively as earthworks. They represent
sophisticated examples of hydraulic engineering during this period and all
surviving coalmill sites are considered worthy of protection.
The Bob Gin Pitt mine drainage system 520m south east of Wallington Hall
is a good example of the type of drainage system operating at coal mines
during the later 18th century before the advent of the steam engine. Only
five examples are believed to survive and the example at Wallington is
both early and remarkably complete. It retains a good range of component
features including a wheel pit, pumping shaft and leat which survive well.
There has been no later development at the site and the remains provide
valuable information on drainage operations during this period. The
survival of a shaft associated with coal workings at Deanham Colliery
enhances the importance of the monument.
Details
The monument includes the upstanding and buried remains of the drainage
system for Deanham Colliery and a shaft situated on the north bank of the
valley of the River Wansbeck. Deanham Colliery was situated beneath and on
both banks of the river, although no further remains are visible today.
The drainage system, also known as a coalmill, which includes a wheel pit,
a pumping shaft and part of a leat, is known locally as the Bob Gin Pitt.
It was installed between 1730 and 1767 to drain Deanham Colliery, one of
three collieries on the Wallington estate in the 18th century. Deanham
Colliery closed in 1774. The pump operated by means of a vertical water
wheel which was fed by a leat from the west.
The remains of the drainage system are visible as a series of prominent
earthworks. The wheel pit survives as a rectangular hollow 11m by 6m and
3m deep with spoil tips up to 1.5m high on the east and west sides. On the
south side, the wheel pit is enclosed by a mound of spoil 1m high; beneath
this mound a stone lined drain runs in a south easterly direction towards
the river, although the exact position of its outfall is uncertain. The
pumping shaft, 6m by 3.5m and up to 2m deep, is rectangular in shape. It
is separated from the wheel pit by a stone wall, visible as the
fragmentary remains of its lower courses. The leat which supplied water to
power the pump lies to the west of the pumping shaft and is visible as a
slightly concave platform, an average of 1.5m wide and up to 0.2m deep,
running along the contour of the valley. A 31m length of this leat is
included in the scheduling including a 5m section which contains a later
stone channel forming a culvert. A mine shaft lies 1.5m north of the leat
and, circular in shape, it measures 4m in diameter and is 1.5m deep. This
is included in the scheduling.
MAP EXTRACT
The site of the monument is shown on the attached map extract.
It includes a 2 metre boundary around the archaeological features,
considered to be essential for the monument's support and preservation.
