Earth Science Partnership Ltd reposted this
North York Moors Jurassic Coal Mining Marc Fawcett, Ian Sharp, M. van der Valk There is a very interesting article by Carl Thomas on the North York Moors Caving Club website describing the coal mining where they worked seams as thin as 6 inches (15 cm). https://lnkd.in/e5k5XvUA The report also gives an indication of tonnages extracted for some areas. It would appear that the 1850's Ordnance Survey maps did not record all the bell pits and most of them are prior to that date. 3D GeoVisionary view of air photo over DTM attached for some of the bell pits on Rudland Rigg.
BOUT THIN COAL SEAMS I worked as a mining surveyor in the late 1950s and the the thinnest seam I experienced was 2'3" thick. [69cm] You can imagine our difficulty in traversing the workings on a face 200m long with a miniature theodolite on a small tripod and with a linen tape to measure the distance between stations. At a neighbouring colliery there were workings in a seam about 45cm thick but I did not have personal experience of this. I do know that a gentleman broke his leg in a roof fall in the middle of the face. One can imagine the pain and difficulty experienced in his evacuation. Shortly afterwards I changed to civil engineering and then specialised in geotechnics, but the bitter experiences of coal mining remain with me; especially because of the fatal and non fatal accidents that befell my uncles.
For bell pits of course the restriction associated with seam height isn't relevant over the footprint of the bell itself. It's only when you start trying to connect workings underground that the thickness of the seam becomes relevant other than in simple economic terms.
Super link, many thanks for raising. As always it's fascinating to see just how thin some worked seams were. Rob Addison peter jones
I know Rose Dale and this part of North Yorkshire very well. I would recommend the Lion Inn on Blakey Ridge to begin and end your Geological excursions.
Great thank you - will have a read through
Thanks Anthony Cooper for sharing - good read. Love this sort of stuff.
Evaporite karst specialist; Independent Consulting Geologist
2wM. van der Valk Yes, it is just south of the area Marc showed, historical map with coordinates attached. 54°20'11.48"N 0°59'37.85"W or National Grid ref 465500,494000