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Lead quarries of the surroundings of Asprieres:
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Pyromorphite site n°1 | 
Polysphaerite |
1. Geographical situation
Asprieres is located in the side N-W of the department of Aveyron, to 10 km surroundings in the south-west of Figeac, near Capdenac (sheets with 1/50 000 Figeac).
2. Geological framework
The various quarries are located at the East Fault of Villefranche de Rouergue, in post-triassic grounds: Vidale, Querbes... are in metamorphic rocks (gneiss leyptinitic and leyptinites, mica schists.).
It acts of a field made up of ten parallel veins, lengthened North-South, of share and of the Batch.
 Pyromorphite site n2 |  Pyromorphite site n2 |
3. Morphology, structure of the ore deposit
It would seem that the principal veins spread on approximately 1000 m. Any information is still available on the total vertical depth of the quarry.
4. Economic substances, production, use:
The site located at Asprieres is known since the Roman time gallo for its lead ore deposits. Indeed, this metal soft, ductile, at low melting point and thus easy to work, with interested the Romans in particular for the manufacture of pipes, but to as manufacture tanks... with the consequences as we know due to lead poisoning.
The historical little of documents on these exploitations makes state of a more important exploitation in Vidale: 700 tons of ore of 1885 to 1920.
 Pyromorphite site n°1 |  Pyromorphite site n°1 |
5. Work
"La
Vidale" is a mine which follows a quartzose seam, and which was recognized
on more 500m. One knows 3 galleries superimposed on a hundred meters height. These
galleries all seemed to communicate between them by interior shaftss, which would
have been filled by spoil at the time of work carried out to remake the way leading
to the martyrdom, a few higher meters.
Querbès, located it also in a quartzose
seam, is an old gallery of a few hundred meters, which is divided into two branches.
The entrance is blown in, drowned under the vegetation.
Other work would seem only of low economic importance, and had not given place to written reports/ratios.
 Pyromorphite site n3 |  Pyromorphite site n4 |
6. Mineralogy
The Asprieres area is known for her pyromorphite. This mineral (lead chlorophosphate) is found under various facies:
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in plating, or crusts on quartz,
- in small small casks,
- in "spheres",
known as facies campilite.
The
color of this pyromorphite can go from the yellow to dark green-chestnut, with
all the intermediate colours.
To note that pyromorphite can sometimes be with
hemimorphite (recrystallizations).
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| Pyromorphite
-centimetric crystals. They are, from times to times, recovered with hemimorphite
(photos to come!). 5 x 3,5 x 3 cm | |
Let us announce that pyromorphite can be mainly found on barite (diaclases in
the seams) and on quartz very brechic.
It is not rare to find galena, but which is generally very faded. It is in the form of blades of cleavage in quartz, or in the form of "flies" disseminated in the wall-rock.
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| Polysphaerite
is a pyromoprhite neighbour :lead and calcium chlorophosphate. The color is "green
apple" and its shape is like "spread".This sort of mineral seems
to be very rare in this area. | |
Sphalerite, cerusite... are also announced, but belong to the micro mineralogy.
Quartz and the barite were also found on various sites.
Lastly, let us note that certain indelicate found judicious "to scrape" a small satellite vein that passes precisely on the level of the martyrdom, at the top of the mountain. It doesn't go without saying that the damage did not pass unperceived, what has as a bad consequence for the mineralogists who prospect in this zone.
7. Bibliographical orientation
Pierrot
R., Pulou R., Barb P. (1977) – Mineralogical inventory of France –
Aveyron.
