As a former teacher of geography & geology knows his subjects extremely well & this showed in his masterly explanation of the industrial past of Great Ayton in a talk comprehensively illustrated with photographs, maps & diagrams.
The village of Great Ayton had all the usual local industries such as bakers, blacksmiths, etc. but in addition its location close to the escarpment of the North Yorkshire Moors provided the raw material for an industry based on the extraction of a diverse range of minerals. The area of particularly focussed upon in the talk was Gribdale, east of Great Ayton. In this area the sedimentary deposits of sandstone, alum, jet & ironstone have been commercially mined for hundreds of years.
High quality sandstone was first quarried by the Norman’s for the construction of the local church & has been incorporated in local buildings ever since. The layer of sandstone was sufficiently thick for long items such as gate pillars & window lintels to be made. Even intricate items such as staircases could be carved from local sandstone.
Alum was extracted from shale by a complex process. After mining the shale was calcined, that is it was mixed with brushwood in a large conical clamp, protected by a veneer of clay, & ignited. After burning for several weeks the aluminium sulphate was leached out with water in steeping pits until a sufficient concentration was attained. This liquor was then transferred to a cistern until impurities had settled. The supernatant was reduced in volume in the boiler house & reacted with burnt kelp to add potassium & human urine to add ammonia before cooling to allow the crystals of alum to precipitate. The resultant alum was used in tanning, to make leather more supple, & in the textile industry as a mordant to fix dyes. It was, apparently, also used therapeutically as a treatment for all manner of diseases.
Jet was extensively mined for jewellery in the Victorian era when it was fashionable following the death of Prince Albert. Ironstone was the last & deepest layer to be exploited & three mines operated in the area from 1860 until 1930 with extraction by galleries leaving pillars to support the roof. The ironstone was transported by overhead ropeway, tram & train to the local blast furnaces.
The final mineral to be mined was whinstone an igneous rock found in a vertical fissure called locally the Cleveland Dyke but in fact stretching across the country from Galloway to the North Sea. This hard rock was ideal, when crushed. to build roads.
The evidence of this repetitive mining of the area is clearly visible as pock marks all over the escarpment but little other physical evidence remains..