NPRN260378
Map ReferenceSO21SW
Grid ReferenceSO2390310269
Unitary (Local) AuthorityTorfaen
Old CountyMonmouthshire
CommunityBlaenavon
Type Of SiteCHIMNEY
PeriodPost Medieval
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Description
Hill Pits, so-called because they were a pair of closely spaced shafts, were sunk in 1835 by Thomas Hill & Son and worked until c1893. The boiler stack relates to a secondary phase of coal winding at the pit, when a steam engine was employed.

Stack base for the boilers at Hill Pits (nprn 88056), approximately 2m square and 7-8m high. Of snecked hammer-dressed sandstone. A projecting plinth course is only visible on the SE side of the base due to the rising ground to the NW side. The base has a projecting band below the top, above which are rounded dressed stones, presumably for a round brick flue. Some other rounded dressed stones area strewn about.

On the SE side the base has a flue opening and offset by 2m is the cast iron frame of a damper plate (no plate is now in situ), but the flue associated with it is only discernible now as a a depression 4m long and 0.5m deep beyond the damper.

The ponds on the N side of the pit suggest that coal was raised initially by water balance lifts. The stack suggests that a steam winding engine was later installed. The stack is therefore probably a secondary feature at the colliery.