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 Bobgins engine house site is the only known survival of a water-powered
beam pumping engine in the North East Coalfield, and is believed to have been
undisturbed since abandonment in the 18th century. It is believed that
valuable technological evidence will survive as buried deposits. The monument,
therefore, offers a rare and valuable opportunity to study the technology of
the water-powered beam pumping engine of the early 18th century.
Details
The monument is situated at the confluence of the Bobgins and Causey Burns,
WNW of Causey, and includes the ruins and buried remains of an early 18th
century engine house which originally housed a water-powered beam pumping
engine. The engine would have consisted of a rocker beam, raised and lowered
by the axle of a waterwheel at one end, and operating pumps in a mineshaft at
the other end.
The bob (beam) gins (engine) engine house is situated at the southern boundary
of the Beckley and Andrew's House collieries. It is believed to date to 1726
since in that year it is recorded that the Beckley colliery was drained from a
shaft in the Andrew's House ground by means of a beam pump powered from an
adjacent burn (later becoming the Bobgins Burn). The Andrew's House colliery
was redeveloped in 1767, and a new beam engine was added to raise water from a
12 fathom shaft, though the earlier beam engine is likely to have continued in
use draining both mines.
The engine house, situated at the bottom of a steep slope, survives as a
pronounced rectilinear mound approximately 13m square and 1.5m high. Though
obscured by dense scrub vegetation, masonry fragments are visible,
particularly at the north east corner which survives to several courses. A
masonry retaining wall built against the slope survives on the western side. A
shaft on the south side, now marked with a concrete post, is an important
component of the layout of the site and is likely to retain technological
evidence around the shaft head.
Modern concrete shaft capping and a concrete post are excluded from the
scheduling, although the ground beneath these features is included.
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.
