Neuil mine
The Neuil Mine, in
Geography
The mine is situated about 1 kilometer north of Neuil, a small hamlet in the commune of Saint-Pardoux-la-Rivière. The main production shaft, at an elevation of 250 meters above sea level, can be reached by following a small valley on the left side of the D 707 Nontron- Thiviers just before arriving at Neuil. The shaft is located on the right-hand side of the small stream; it is fenced in and closed to the public because of its hazardous nature.
Mine works
The partially collapsed main shaft was once 47.50 meters deep and led to three exploitation levels. An additional horizontal access is now flooded.
The ore was taken to Nègrecombe, washed and then transported by train (on the now redundant railway line Angoulême-Thiviers) to a smelting plant.
History
The mine was in operation mainly between 1921 and 1928, between 1956 and 1959 and once more between 1976 and 1984. Several hundred tons of ore were mined. The reserves are estimated at several thousand tons.
Geology
The Neuil Mine is emplaced in
The lodes of the Neuil Mine are no single occurrence. To the northwest (towards Nontron) several other lodes follow, which were also mined (Le Puy Mine, Cantonnier Lode, Tabataud Quarry among others).
Mineralogy
The central part of the lode consists of a
The mineralisation is due to hydrothermal circulation in the temperature range 150 – 300 °C. The ores were deposited in two stages, each with a characteristic paragenesis: a higher temperature stage with galena and quartz and a lower temperature stage with baryte and marcasite. These minerals are accompanied by sphalerite, pyrite and chalcopyrite. The ore therefore belongs to the mineralisation type sphalerite-pyrite-galena-chalcopyrite.
Age
A
Conclusion
The spatial arrangement of the lodes points towards local southeasterly extension within the basement rocks. By that time the paragneisses had cooled down to below 300 °C. Additionally the lodes experienced shearing motions as shown be the mylonitized edges. This fact combined with the variations in strike possibly hints at a shear zone oriented southeast: the lodes following N 065 can then be interpreted as antithetic surfaces, whereas the lodes following N 045 are probably R'- Riedel shears. Furthermore the fairly steep northwesterly dip of the lodes hints at a top to the southeast sense of motion ("bookshelfing").
The mineralizing hydrothermal solutions most likely came from the Piégut-Pluviers Granodiorite.
Literature
- Guillot, P. - L. et al. Feuille Thiviers. Carte géologique de la France à 1/50000. BRGM
- Legrand, N. et al. (2008). Minéralogie des Mines du Nontronnais, Dordogne. Le Règne Minéral, vol. 84, Munich.