Bonsall Leys Lead Mines

My first venture out was on the 9th of March 2017 to visit Bonsall Leys Lead Mines situated south east of the village of Bonsall in Derbyshire.  The old mines lie on Bonsall moor in the immediate area north of the right angle bend of Leys Lane, as shown on the map below, and consist of a scattering of small shafts with associated spoil heaps and a series of rakes (lengthy shallow excavations into the ground in pursuit of surface ore veins).  A parking space is available right on the bend and is large enough for a couple of cars.




The area is popular with walkers and is criss-crossed with footpaths.  The Limestone Way cuts across the moor on its way from Castleton in North Derbyshire to Rocester in North Staffordshire.

THE LIMESTONE WAY ON BONSAL MOOR

VIEW ACROSS THE MOOR TO BONSALL VILLAGE

Background

Lead mining dates back to the Roman times in Derbyshire but has an extensive history from post Medieval times to the 19th Century.  Most of the working here appear to have been fairly small scale and dates back to Medieval times but has probably been re-worked many times over as the mining and smelting techniques improved and allowed for the extraction of lower grade ores which were previously ignored/discarded.

Where mineral veins were evident from the surface the ore was mined by excavating along the vertical veins, often referred to a Rakes, leaving long cuts in the landscape.  Along side these are many shallow shafts and associated spoil heaps where attempts have been made over time to locate or intersect further veins underground.

I believe most of the shafts were left open up until the 1980s when they were covered with concrete railway sleepers to protect the public.  They appear to be generally about 1.5 metres in diameter and stone lined.

MINE SHAFT COVERED WITH SLEEPERS

SHAFT LINING - VIEWED THROUGH A GAP IN THE SLEEPERS

COVERED SHAFT WITH ANOTHER SHAFT AND CIRCULAR SPOIL HEAP IN BACKGROUND

THE START OF A RAKE WHICH EXTENDS FOR SOME DISTANCE BEYOND THE TOP OF THE PICTURE

EXTENSIVE SMALL WORKINGS COVER THE AREA - NOW MOSTLY OVERGROWN

Mineralogy

The area was extensively mined for the Lead ore Galena although there is mention of Calamine (Smithsonite - a Zinc Carbonate usually formed through the alteration of Zinc Blende) also being present in this area but I'm unsure if this was ever in sufficient quantities to be of economic significance.  Associated with the metallic ores are the minerals Fluorspar and Baryte.


Minerals found

I found the majority of the spoil heaps to be devoid of any mineral content, probably due to being reworked many times and extensively picked over through the years.

Only one heap revealed any evidence of mineralization with the results shown below:

GALENA WITH BARYTE

A SOMEWHAT WEATHERED SPECIMEN OF FLUORSPAR WITH BARYTE

Some useful references

Link to Historic England's Bonsall Leys lead mines

Link to A survey of surface features at Fools Venture Mine