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Coal Balls and Todmorden Moor
- A Geologically Designated Site

Pointers towards a West Yorkshire Geological
Designation for Todmorden Moor.

In Summary:

  • Coal balls are a rare phenomenon (Bolton Museum web site).
  • Todmorden Moor was on the eastern limits of the Lancashire coal field, and coal balls are still found there in the old coal wastes.
  • Coal balls are not associated with other mines in West Yorkshire and are rare across the whole of the UK.
  • This mining site, unlike mines closer to the towns or in the valleys has not been redeveloped or tidied up.  It is on Common Land and easily accessible.
  • Coal Balls and prepared specimens from the area were donated to the Bolton Museum by James Lomax , who also organised a coal ball study visit to Todmorden Moor Mine for the British Association for the Advancement of Science in 1903.
  • Interest in coal balls continues even after the closure of the mining industry because of :

a) Geological interest in the formation of these rare fossil bearing nodules.
b) Palaeobotanical interest in fossil evidence within the coal balls.
c) Local heritage interest as the evidence for a major industry disappears from the landscape and experience of local people.

What are Coal Balls?
In brief, coal balls are extremely hard concretions found within certain, but by no means all, coal seams that were overlaid by marine strata - and are described by Scott and Rex (1985) as "exceptionally preserved calcareous permineralised peat". They vary in size from 2 inches to 2 feet in diameter, often circular or elliptical but sometimes irregular in shape (Iain Williamson "Coal Mining Geology" p.63). Many are found to contain excellent evidence of plant structures completely petrified by secondary carbonate materials and clearly show the delicate tissues of bog flora of the carboniferous period.

Where are they found locally?
Coal balls are associated in the UK with Central East Lancashire, particularly the Burnley area where they were often in some concentration. The seams concerned are the Upper Foot and Lower Mountain Mines of East Lancs.  The Todmorden Moor collieries were on the eastern edge of this coal field.

Their presence within the local coal seams could, and did, result in seams becoming unworkable because of the damage to mining machinery.  As late as 1967 the Colliery Guardian ran articles on efforts to overcome the very expensive damage to picks, drums and cutting jibs in the N.E. Lancs. coal workings.

Coal balls occurred quite frequently in the Todmorden Moor mines and local people used to collect them from the coal wastes.  Many may still lie hidden within those waste heaps.

Academic interest:  After first being identified in the UK in 1855, (Hooker and Binney) coal balls have been discovered and studied in several European countries and the US.

Many fine examples of fossil bearing coal balls from this area have been transferred to universities in American and New South Wales for study (information from Towneley and Bolton Museums).

A visit to Todmorden Moor by Marie Stopes is recorded in her 1962 biography. Todmorden Moor was chosen for a visit to do research work on fossils from the carboniferous period.  Her expedition to Todmorden Moor for this purpose led to her paper to the British Association Meeting in York in 1906 and her publication on the formation of coal balls - Stopes and Watson: Royal Society 1908. 

Her work remains a clear, but no longer definitive, explanation of the origin and chemical formation of coal balls. Work done in the 1970s and 80s on European and US coal balls has continued to examine the complex chemical origin of this phenomenon. As Scott and Rex state "No current model for the formation of coal balls completely explains their occurrence and rarity ……….."

Regional Historical Interest:   Most colliery sites in the area are now almost, or completely invisible, only identifiable from map evidence and mining histories. Even the high moorland mining sites have slowly disappeared under grasses and peat bogs, leaving little evidence apart from unnatural irregularities in the landscape, and trial holes and bell pits across parts of the moorland. A whole industry has all but vanished.

Unlike disused lowland colliery sites, there has been no land re-use or restoration work carried out after the moorland mines were abandoned.  One of the last to close, in 1964, was Sandy Road Colliery in the centre of Todmorden Moor.  This mine site has not had time to disappear into the landscape. Mounds of colliery wastes disfigure the moorland - too steep and acid for regrowth of vegetation.  The foundations of a small mine building remain, and unidentified metalwork at the top of the colliery tramway (now removed, but still marked on many maps).  No other evidence of the mine exists above ground, and the entrance to Todmorden Moor mine has been blocked up for safety reasons. The evidence is in the memories of local ex-miners and their families.

Todmorden Moor was designated as Geological Site in 2009 by the West Yorkshire Geology Trust.