Lead and Silver

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The main productions of Castel-Minier are unquestionably the silver and the lead. It is not still possible to draw up the operating chain organized on this site. On the other hand, the excavations delivered elements which characterize various operations realized on these two metals.

Slagy elements
The distinction between the slags from ferrous and non ferrous metallurgy is not so easy to do as it appears to it at first sight. Slagy elements which were abandoned are mainly fragments of wall, which it is rare to be able to attribute to a specific metal production thank to a simple visual inspection. For the slag itself, the level of change, with in particular the implementation of a white patina, makes sometimes difficult the distingo between slag, blacklead ore and plumbiferous residues. In fact, the totality of non-ferrous slag found represent only 500g. We distinguish by simple macroscopic examination 5 types of not ferrous slags bound to the reduction. By following the image below, we note from left to right, crystallized grey slag, crystallized black slag, bubbling slag with whitish plumbiferous encrusting and a bluish heavy plumbiferous slag. The last class, not represented, is a black glassy slag.
 scoriacés Elements


Litharges (??)
The litharge is an oxide of lead created artificially during the coupellation (??). It can be so marketed for the glaze realization, serve of fondant in the reduction phase of blacklead ore or to be revivified to obtain from some blank (unsilvered ?désargentée ??) lead. It is thus either a by-product, or an intermediate product but not a waste.
Since the beginning of the operations in Castel-Minier, we found about forty fragments representing a little less than 400 g. All the samples are covered with a layer of whitish deterioration and present characteristic cracks of this product deterioration. They give evidence of the reality of the lead's work on these zones.
Litharge
Litharge


The break-in of coupellation (??)
The most spectacular discovery was an important lot of break-in of coupellation. It is the base of a sole of an oven of coupellation. Realized in ash, it stuffs itself with lead during the refining of the lead of work (???). This type of sole is single-use. We had discovered one only fragment in 2011. Today, we décombre more than about fifty for a superior mass in 3kg.
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The lead
Numerous fragments of metallic lead were found. We have at the moment a first corpus of metallic lead distributed on all the chronological sequence of the site. Two lead types can live on this site: the lead of work and the revivified lead. The first one must be argentiferous at rates exceeding 1000 ppm. It arises from the phase of fusion of ores. It should be relatively rare because it is a silver rich intermediate product. The second results from the reprocessing of litharges (???) to obtain some lead metal. It arrives at the end of operating chain. You should not either omit lead the origin of which is not to be looked on the site (objects of the common(current) life, the elements of the construction etc.).
The lead ingot (910 g) which we found is relatively pure (99,76 mass Pb). With only 225 ppm of money(silver) (0,022 % Ag), we characterize a lead of revivification. He(it) so takes place in extreme at the end of production line, one time as the money(silver) was got back and as the litharge was retransformée lead.
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Metallurgical ceramic
In the high part(party) of the site, we identified fragments of pocket of casting. His(her,its) shards result from ceramic which were not turned(shot). All the discoveries concentrate in the same place of the site: in the contact of a wall in the high part(party) of the site. They were all found in levels of the end of XIVth s For each, the dough is unrefined aves of the grease removers among which some exceed(overtake) the centimeter. The internal surface is grésée under the influence of the fire(light).
The determination of the diameter cannot be exactly made. It is understood(included) that between 20 and 30 cms what gives an already very respectable dimension(size) to these pockets. By referring to our studies on the melting pots of Montreuil-Bonnin and the monetary workshop(studio) of La Rochelle, the mass which can be put melting exceeds(overtakes) 11 kg.
In these metallurgical ceramic rooms(parts,plays), it is advisable to add two fragments of melting pot still holding balls of money(silver).
Fragments de poche de coulée
Fragments de poche de coulée
Fragments de creuset
Fragments de creusets