Ironbridge and the Ironbridge Gorge is on the south side of Telford (a new town whose development started in the 1960's), although the towns and villages that make it up are much older and have a rich history of underground working, none more so than the towns of Madeley and Ironbridge.
The Pennystone Ironstone Adit, Ironbridge is not indicated on any known map or mine plan and is unlikely to have been active since the early 19th Century. The adit entrance is a brick-arch on St. Lukes Road, Ironbridge.
The Remains Today
When first entered in the 1980's the adit mouth was almost blocked with rubbish and dead vegetation and the air was poor. Local residents believed that it would be flooded and that the whole area of Hodge Bower above the mine was located over a large lake. Recent explorations indicate that this may well be true!
The tunnel itself is about 2m high and 1 to 2m wide - although there is substantial collapse and much evidence of fractured roof.
The first 60m is fairly dry but muddy underfoot with about 20m of brick arched support, then about 20m dry stone walling with natural sandstone roof and finally 20m in natural rock.
Here the lower half exposes the shale bed which is very weathered but still shows some stratification, ironstone bands and ironstone balls. Although previous working and gobbing (back filling) cannot be ruled out it is not clear that this has occurred along the exposed or the stone walled sections.
Several niches or alcoves exist but there is no evidence of side passages throughout the explored section. Two 'chimneys' occur near the entrance each about 1 metre square in area and up to 3m high, their purpose is not clear but one seems to have a drain cover on top.
The two major falls consist of large sandstone blocks, but throughout the exposed lengths collapses of shale have occurred.
From 60m the floor is covered with water deepening as the strata dips into the hill, while the tunnel stays just beneath the sandstone bed. For 30m the water is less than waist deep and the tunnel is fairly straight although it veers to the left and this continues as far as can be seen.
At about 20m into the flooded section there is a conical depression in the floor about 1m deep but it can be by-passed by making footholds in the clay on the right-hand wall (beware - when first entered the water is clear, but a wave travels in advance of the explorer stirring up the mud so that holes in the floor cannot be seen!).
Several metres further on, with only 0.5m of air space, there is a straight-walled shaft underfoot possibly at least 3m deep. Attempts to cross this by swimming and by bringing inflatable canoes in have not been successful for various reasons.
The cause or purpose of these depressions is not clear but they could be 'crown-hole' collapses into lower workings. The strata down to the Crawstone Seam, about 30m beneath, could contain up to 10 other worked seams and void migration (frequently aggregates below the Big Flint Sandstone) may have occurred. At Lawley (on the west side of Telford) up to 11m of vertical space is known for example at this horizon.
The tunnel can be seen to continue beyond this shaft, the airspace continues to reduce and a fall of sandstone blocks further view. This may however be climbable or there could be a continuation on the left-hand side, but this cannot be seen as it is around a corner.
Features of interest seen on early visits included:
- a 300m dia. fossilised tree trunk at about 30m in.
- several pieces of rotten timbers possibly remnants of early roof supports.
- a candle-sized niche with smoke marks 60m in.
- some black tarry matter on rocks and floating on the water - which is typical of Big Flint Strata.
- many coalified pieces of fossil in the sandstone.
- 150m in, brown ironstone band and ironstone nodules of various sizes.
Report & Sketch: Ivor Brown
Bad Air - mainly Oxygen deficiency has been recorded in this adit. Explosive gases are also possible due to the proximity of coal seams.
Local residents reported seeing bats in the area, and some were found in the tunnel length examined. They could well survive in the fissures and beyond the limits of exploration. DO NOT disturb them, particularly during the hibernation season.