Details

The monument is situated on the south west outskirts of the village of
Pontesford. It includes the standing and buried remains of the Nag's Head
engine house, which was originally part of the former Pontesford Colliery. The
engine house is one of a group of early engine houses in the village and is
thought to be the earliest, dating to the 1790s. The others have been
converted to dwellings, and the Nag's Head engine house is the only one to
survive unaltered.

The building survives to a height of around 10m. The engine house is of stone
to first storey level, but the arched opening in the south west wall which
accommodated the pivoting beam of the engine is of brick. A lean-to structure
on the north west side, also of brick, has been interpreted as either a boiler
house or blacksmith's workshop. The engine house retains internal details,
including engine fittings and a condenser pit, which provide valuable
technological information about the type of engine installed in the building.

It is understood that the machine was either a Newcomen atmospheric engine or
a Boulton and Watt steam engine. The former was the earliest type of `steam'
engine generally employed in mine drainage, but was not strictly steam
powered. Steam was let into a closed cylinder attached by a piston to the
engine beam, and was then condensed to create a partial vacuum, allowing
atmospheric pressure to push the piston down into the cylinder and raise the
beam end. Boulton and Watt developed a more efficient engine in which
sufficient steam pressure was generated to raise the piston on its own,
although atmospheric pressure still produced much of the engine's motion. The
unaltered Nag's Head engine house and its internal fittings are therefore
unusual survivals from a period of technological experimentation and
advancement.

All fence posts, field walls and modern structures such as greenhouses 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.

Source: Historic England

Reasons for Scheduling

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.
The term `nucleated' is used to describe coal mines that developed as a result
of increased capital investment in the 18th and 19th centuries. They are a
prominent type of field monument produced by coal mining and typically
consist of a range of features grouped around the shafts of a mine. The
simplest examples contain merely a shaft or adit with associated spoil heap.
Later examples are characterised by developed pit head arrangements that may
include remains of engine houses for pumping and/or winding from shafts,
boiler houses, fan houses for ventilating mine workings, offices, workshops,
pithead baths, and transport systems such as railways and canals. A number of
later nucleated mines also retain the remains of screens where the coal was
sized and graded. Coke ovens are frequently found on or near colliery sites.
Coal occurs in significant deposits throughout large parts of England and this
has given rise to a variety of coalfields extending from the north of England
to the Kent coast. Each region has its own history of exploitation, and
characteristic sites range from the small, compact collieries of north
Somerset to the large, intensive units of the north east. A sample of the
better preserved sites, illustrating the regional, chronological and
technological range of nucleated coal mines, together with rare individual
component features are considered to merit protection.

The Nag's Head engine house is one of a notable group of late 18th and early
19th century pumping engine houses within Pontesford, and the only one to
survive without alteration. The interior of the building will retain buried
deposits relating to the technology employed at the mine. It preserves
internal fittings and technological information relating to the operation of
late 18th century engines.

Source: Historic England

Sources

Books and journals
Brown, I J, 'Journal 1976' in The Pontesford Mine Engine House near Shrewsbury, (1976), 22-24
Davies, T et al, 'Mining Remains in SW Shropshire' in Pontesford Colliery, , Vol. 18, (1993), 49-53
Other
Notes from fieldwork, Instone, Eric , Pontesford Engine Houses, (1994)

Source: Historic England