Ecton Copper Mine in Staffordshire was in its heyday in the late 18th Century, both the deepest mine in Europe but also the most productive copper mine. The brecciated pipe-like chalcopyrite body was mined out forming an irregular chamber up to 180m by 35m wide.
The vast majority of the mine complex is now flooded but the upper part can be accessed via Salt’s Level which was driven as an adit from the dressing tables on the hillside to the main shaft below the Boulton & Watt steam engine driving winding gear on the top of the Ecton Hill.
The host rock is Dinantian Carboniferous Limestone which generally is quite flat lying but in the vicinity of the orebody becomes tightly folded. Although the ore genesis is not well known, mineralisation here appears to be associated with localised folding.
Salt’s Level was driven by two brothers called Salt, driving a metal spike into the limestone with a sledgehammer to create shot holes and then blasting with black powder. Ecton was one of the first recorded mines to use black powder as a charge.
They drove the shaft at about 2m a week, straight to the main winding shaft with a quick detour when they crossed galena and chalcopyrite bearing veins.
The main winding shaft.
Salt’s Level then connects to the top of the Ecton pipe orebody (the section shown on the mine plan above). This orebody had been worked downwards from an exposure on the top of the hill. (The metal in the centre of the image is an old tractor dumped by a farmer down the shaft).
Although the main orebody is well below this level, there is still evidence of copper mineralisation.
The Salt’s Level can be accessed by contacting the Ecton Hill Field Studies Association who also run sessions for school children on the geology of Ecton and the chemistry of ore minerals (and black powder!).
Further Reading: Ford, T.D., 2000. Geology of the Ecton and other North-east Staffordshire Mines. The Bulletin of the Peak District Mines Historical Society, volume 14, number 4, 1-22.