Mines and minerals in Derbyshire (UK): May 2017

The 10th of May, 2017 found me exploring Milltown Quarry near Ashover. It lies between Gregory Mine a half mile to the west and Fallgate Quarry a quarter of a mile to the north east. Although not a mine; it has been the source of some very interesting mineral discoveries in the past, as has Fallgate Quarry too. This is due to the quarrying process exposing mineral veins or rakes.

Stars Wood Mine was located just to the side of the Milltown Quarry and exploited some of the same minerals.

The quarry is divided into two parts, the old quarry and the more recent quarry. The older quarry was the source of the interesting mineral discoveries back in the 1980s. However, the floor of the quarry has since been filled with 2m of industrial Fluorspar slurry, burying the main exposed rake where the discoveries were made. Extreme caution should be exercised when exploring here as most of the quarry floor area has been fenced off with Danger: Quicksand warning signs.

There are not many places to park in this area but I managed to find a convenient parking place opposite the Miner Arms Inn's car park where there is space for two vehicles. It's within easy walking distance of the quarry.

Background

Limestone appears to have been quarried here from the 1880s and Flourspar and Calcite were also commercially extracted. Star Woods Mine was located just south of the old quarry and both used the Ashover Light Railway to transport material down to Clay Cross. The mine extracted Galena, Fluorspar and Calcite.

The quarry was worked up until 1936 and apart from a brief working life during the war years has remained closed ever since. A new quarry was started up to the west of the old one and was in use up until 2003.

The mineral veins exposed by the quarrying contained, I believe, mainly Fluorspar and Calcite with smaller quantities of the Lead ore Galena. However, in the 1980's a one meter length of the Blackwells Vein exposed on the quarry floor produced an extraordinary variety of unusual minerals which are detailed on this mindat page.

Access to this vein is now impossible as the quarry was used as an industrial dumping ground for Fluorspar slurry in the 1990s to a depth of 2 meters.

Mineralogy

The quarry predominantly contains examples of Fluorspar and Calcite with some Galena present. Quartz and Baryte are also present in smaller quantities. Some fine specimens of Fluorspar have been found in the past. The more exotic minerals found in the 1980s appear to have been confined to that specific section of the Blackwell vein and as such it's unlikely they will be found elsewhere on the site.

Minerals found

The site proved very interesting with evidence of large scale mineralisation around a major rake passing through the quarry which has been extensively worked in the past.

I found whole rock faces along faulted planes covered with Fluorspar and/or Calcite crystals.

Galena, Barytes and Quartz was also evident in rock samples littering the floor.

Some useful references

Milltown Limestone Quarry (Some info on the quarry on the aditnow site)

Milltown Quarry (The mindat entry and mineral list)

VILLAGE SIGN WITH ITS OWN FLOWER BOX
HOW QUINTESSENTIALLY ENGLISH

THE RIVER AMBER RUNS ALONG SIDE THE ROAD HEADING NORTH OUT OF MILLTOWN

THE TRACK LEADING TO THE QUARRY

MILLTOWN QUARRY

VIEW OF THE WESTERN FACE OF THE QUARRY

THE NORTH FACE OF THE OLD QUARRY
VERY MUCH OVERGROWN NOW

COWSLIP (PRIMULA VERIS) GROWING WILD IN THE QUARRY

A WELL WORKED MINERAL VEIN

PRETTY MUCH THE WHOLE OF THIS ROCK FACE IS
COVERED IN FLUORSPAR CRYSTALS

A CLOSE UP SHOWING THE FLUORSPAR CUBES

CALCITE CRYSTALS ON ROCK FACE

LARGE FLUORSPAR CUBES WITH INCLUSIONS

MORE MILKY COLOURED ONES

A MORE ATTRACTIVE COLOUR

QUARTZ FILLED NODULE

THIN VEIN OF GALENA IN FLUORPSAR

FLUORSPAR WITH BARYTE AND QUARTZ CRYSTALS

On the 5th of May, 2017 I visited Gregory Mine near Ashover which is set in dense woodland and over looked by a large rock buttress known locally as Cocking Tor.

The mine site can be approached from three different directions, along the woodland path that runs from Gin Lane in the Ashover direction, from the opposite end of the path on Holestone moor via the track alongside Red House Farm, or from the bottom of the valley directly below the mine site which is also accessed from Gin Lane.

I parked on the grass verge just up the track at the side of Red House Farm and walked from there, with Gregory mine about a 12 minute walk away through attractive countryside with good views over Ashover Hay to Ogston reservoir. Note this track is not fit for motor vehicles!

Background

Gregory mine is an old Lead mine which appears to have been worked from the early 1700s and certainly continuously from 1734 to 1803. In it's time it was one of the most productive Lead mines in Derbyshire. Little currently remains of the original mine with the only structure still left standing being a chimney.

In its hay day the mine was said to have produced over 500 tonnes of ore a year and was very profitable. However, towards the end of the 18th century the main vein was exhausted and despite the discovery of a new vein it's extraction was deemed not financially viable and the mine closed in 1803.

The whole area is now fairly overgrown and seems to support a good variety of wildlife and plants.

Mineralogy

The main ore mined was Galena and as far as I'm aware was the only ore of economic value during its working life. Zinc Blende, Pyrite and Chalcopyrite are reported to be present in small quantities along with Fluorspar, Calcite and Quartz. Enargite, Wurzite and Pyrobitumen have also been cited as being found at this mine.

This is a description of the mine taken from "A General View of the Agriculture and Minerals of Derbyshire Volume 1" by Farey, originally published in 1811:

Gregory (mine) at Overton, in Ashover, in 1st Grit, Shale and Lime, much Lead, Antimoniated Lead Ore? Ore in Shale, two ribs of Ore of different kinds, transparent Flour (spar) with Silvery Pyrites, large Crystals of Calc. Spar, Slickensides, Bitumen in 1st Lime, a Shaft 300yards deep!, a large hillock. Ref link

Minerals found

The site is littered with small areas of exposed spoil with much of it showing signs of mineralisation. Galena is evident along with some Zinc Blende and I did find a single example of a very silvery looking pyrite. There are signs of quartz and ample evidence of fluorspars of various colours ranging from clear to amber to rose pink and deep purple.

The fluorspar in parts is attractive enough to warrant a revisit to see if I can find some better examples. Most of the crystalline examples I found were very small.