Misplaced Pages

Société des mines et fonderies de Pontgibaud

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.

The Société des mines et fonderies de Pontgibaud (Pontgibaud Mine & Foundry Company) was a French silver and lead mining and smelting company based in Pontgibaud , Puy-de-Dôme. It mined lead-silver ore deposits that had been exploited since Roman times. Later it opened another factory in Couëron in the Loire estuary, and then closed down the Pontgibaud mines and foundry. The Pontgibaud factory in Couëron diversified into other non-ferrous metal products using imported ore. After being sold and resold it finally closed in 1988.

#448551

77-611: Pontgibaud is in the Massif Central on the banks of the Sioule river. The belts of ore extend for about 10 kilometres (6.2 mi) north-south parallel to the course of the Sioule on both sides of Pontgibaud. The silver galena veins are embedded in gneissic rock. The different veins of ore at Pranal, Barbecot, Roure, Les Rosiers, La Miouse and Villevieille are mainly oriented in a north-south direction. The ores are encased in migmatites from

154-537: A brilliant, sparkling effect as each cut facet in cut glass reflects and transmits light through the object. The high refractive index is useful for lens making, since a given focal length can be achieved with a thinner lens. However, the dispersion must be corrected by other components of the lens system if it is to be achromatic . The addition of lead oxide to potash glass also reduces its viscosity , rendering it more fluid than ordinary soda glass above softening temperature (about 600 °C or 1,112 °F), with

231-450: A large concentration of around 450 extinct volcanoes. The Chaîne des Puys (near Clermont-Ferrand ), a range running north to south and less than 160 km (60 sq mi) long, contains 115 of them (monogenic volcanoes only). The Auvergne Volcanoes regional natural park is in the massif. The amusement park of Vulcania near Clermont-Ferrand allows visitors to discover this natural heritage and introduces them to volcanology. In

308-433: A linear expansion coefficient of between 5 and 7×10 /°C, compared to 9 to 10×10 /°C for alkali glazes. Those of earthenware ceramics vary between 3 and 5×10 /°C for non-calcareous bodies and 5 to 7×10 /°C for calcareous clays, or those containing 15–25% CaO. Therefore, the thermal contraction of lead glaze matches that of the ceramic more closely than an alkali glaze, rendering it less prone to crazing. A glaze should also have

385-440: A low enough viscosity to prevent the formation of pinholes as trapped gasses escape during firing, typically between 900 and 1100 °C, but not so low as to run off. The relatively low viscosity of lead glaze mitigates this issue. It may also have been cheaper to produce than alkali glazes. Lead glass and glazes have a long and complex history, and continue to play new roles in industry and technology today. Lead oxide added to

462-455: A major study on the ringing of the lead crystal in 1958. Since the potassium ions are bound more tightly in a lead-silica matrix than in a soda–lime glass , the former absorbs more energy when struck . This causes the lead crystal to oscillate , thereby producing its characteristic sound. Lead also increases the solubility of tin , copper , and antimony , leading to its use in colored enamels and glazes . The low viscosity of lead glass melt

539-460: A modest pension. At first the Sioule and its small tributaries were used to power machinery, and horse power was also used to power the hoists. Powerful Cornish-type steam pumps removed water from the 250 metres (820 ft) deep Alice and Taylor pits at Brousse and Roure. Compared to coal the lead/silver mines were relatively safe, with no gas or explosions, and few collapses. The main danger came from rising carbon dioxide. The price of lead fell and

616-610: A pottery or ceramic glaze . Lead glazes first appear in first century BC to first century AD Roman wares, and occur nearly simultaneously in China. They were very high in lead, 45–60% PbO, with a very low alkali content, less than 2%. From the Roman period, they remained popular through the Byzantine and Islamic periods in the Near East , on pottery vessels and tiles throughout medieval Europe, and up to

693-414: A reservoir and two streams. The residues there included dark and vitrified unprocessed material and fine, yellowish sands from the washing. The process of securing the entire district was expected to take over 10 years. Between 1886 and 1891 César de Pontgibaud had the old donjon, which had been abandoned since the time of Louis XIII, restored by a disciple of Eugène Viollet-le-Duc . The more recent château

770-515: A small metallurgical plant in Nantes , and in 1860 founded a non-ferrous metal foundry at Couëron . The Couëron lead foundry employed 160 workers in 1863. At first only lead was to be processed, but in 1878 a copper factory was added, and the company began importing refined copper and zinc. It manufactured copper locomotive boilers and electrical wire, and lead, copper and brass wires, tubes, bars and plates for sale to many other companies. The new owners of

847-569: A working point of 800 °C (1,470 °F). The viscosity of glass varies radically with temperature, but that of lead glass is roughly two orders of magnitude lower than that of ordinary soda glasses across working temperature ranges (up to 1,100 °C or 2,010 °F). From the glassmaker's perspective, this results in two practical developments. First, lead glass may be worked at a lower temperature, leading to its use in enamelling , and second, clear vessels may be made without trapped air bubbles with less difficulty than ordinary glasses, allowing

SECTION 10

#1733084756449

924-406: Is a variety of glass in which lead replaces the calcium content of a typical potash glass. Lead glass contains typically 18–40% (by mass) lead(II) oxide (PbO), while modern lead crystal , historically also known as flint glass due to the original silica source, contains a minimum of 24% PbO. Lead glass is often desirable for a variety of uses due to its clarity. In marketing terms it

1001-601: Is an old massif , formed during the Variscan orogeny , consisting mostly of granitic and metamorphic rocks . It was powerfully raised and made to look geologically younger in the eastern section by the uplift of the Alps during the Paleogene period and in the southern section by the uplift of the Pyrenees . The massif thus presents a strongly asymmetrical elevation profile with highlands in

1078-601: Is booming, taking advantage of the UNESCO heritage classification of the volcanoes of the Chaîne des Puys and the Causses and Cévennes region. The entire economy of the Massif Central has benefited from the opening of roads, particularly the construction of the A75motorway on which is located the famous Millau Viaduct . Lead glass Lead glass , commonly called crystal ,

1155-440: Is frequently used in light fixtures . Lead may be introduced into glass either as an ingredient of the primary melt or added to preformed leadless glass or frit . The lead oxide used in lead glass could be obtained from a variety of sources. In Europe, galena , lead sulfide, was widely available, which could be smelted to produce metallic lead. The lead metal would be calcined to form lead oxide by roasting it and scraping off

1232-488: Is often called crystal glass . The term lead crystal is, technically, not an accurate term to describe lead glass, because glass lacks a crystalline structure and is instead an amorphous solid . The use of the term remains popular for historical and commercial reasons, but is sometimes changed to simply crystal because of lead's reputation as a toxic substance. It is retained from the Venetian word cristallo to describe

1309-443: Is the reason for typically high lead oxide content in the glass solders . The presence of lead is used in glasses absorbing gamma radiation and X-rays , used in radiation shielding as a form of lead shielding (e.g. in cathode-ray tubes , thus lowering the exposure of the viewer to soft X-rays). In particle physics , the combination of the low radiation length resulting from the high density and presence of heavy nuclei with

1386-499: The French Industrial Exposition of 1834 awarded the count a gold medal for his enterprise. In 1838 Pallu et Compagnie, a société en commandite headed by Alphonse Pallu, took over the mining concession and the foundry. At that time four silver-lead mines were in operation. Although Pallu extracted significant amounts of silver and lead, the business was undercapitalized and the mines began to flood. Pallu did not have

1463-547: The birthplace of the glass industry . The earliest known example is a blue glass fragment from Nippur dated to 1400 BC containing 3.66% PbO. Glass is mentioned in clay tablets from the reign of Assurbanipal (668–631 BC), and a recipe for lead glaze appears in a Babylonian tablet of 1700 BC. A red sealing-wax cake found in the Burnt Palace at Nimrud , from the early 6th century BC, contains 10% PbO. These low values suggest that lead oxide may not have been consciously added, and

1540-564: The litharge . In the medieval period lead metal could be obtained through recycling from abandoned Roman sites and plumbing, even from church roofs. Metallic lead was demanded in quantity for silver cupellation , and the resulting litharge could be used directly by glassmakers. Lead was also used for ceramic lead glazes. This material interdependence suggests a close working relationship between potters, glassmakers, and metalworkers. Glasses with lead oxide content first appeared in Mesopotamia ,

1617-734: The regions of Auvergne-Rhône-Alpes , Bourgogne-Franche-Comté , Nouvelle-Aquitaine and Occitania . The largest cities in the region are Clermont-Ferrand , Limoges , and Saint-Étienne . In the Massif Central, the industry remains little developed except locally (metallurgy in Saint-Étienne; tires in Clermont-Ferrand , headquarters of Michelin , world leader in the sector; aeronautics industry in Figeac , etc.). The other industries present are linked to agriculture ( Groupe Limagrain ,

SECTION 20

#1733084756449

1694-457: The 19th century methods of extracting the ore and processing it to make silver ingots. It displays samples of the equipment and minerals, along with explanatory panels and maps. Massif Central The Massif Central ( French pronunciation: [masif sɑ̃tʁal] ) is a highland region in south-central France consisting of mountains and plateaus. It covers about 15% of mainland France. Subject to volcanism that has subsided in

1771-852: The Continent, and traditional glassmaking centres in Bohemia began to focus on colored glasses rather than compete directly against it. The development of lead glass continued through the twentieth century, when in 1932 scientists at the Corning Glassworks , New York State, developed a new lead glass of high optical clarity. This became the focus of Steuben Glass Works , a division of Corning, which produced decorative vases, bowls, and glasses in Art Deco style. Lead-crystal continues to be used in industrial and decorative applications. The fluxing and refractive properties valued for lead glass also make it attractive as

1848-685: The European Union, labelling of "crystal" products is regulated by Council Directive 69/493/EEC, which defines four categories, depending on the chemical composition and properties of the material. Only glass products containing at least 24% of lead oxide may be referred to as "lead crystal". Products with less lead oxide, or glass products with other metal oxides used in place of lead oxide, must be labelled "crystalline" or "crystal glass". The addition of lead oxide to glass raises its refractive index and lowers its working temperature and viscosity . The attractive optical properties of lead glass result from

1925-520: The Middle East. The fundamental compositional difference between Western silica- natron glass and the unique Chinese lead glass, however, may indicate an autonomous development. In medieval and early modern Europe , lead glass was used as a base in coloured glasses, specifically in mosaic tesserae , enamels, stained-glass painting, and bijouterie , where it was used to imitate precious stones . Several textual sources describing lead glass survive. In

2002-547: The Paris bankers Ernest Andre and Paul Bontoux. The four English directors were Charles Morrison, Octavius Ommanney, William Thompson (MP) and John Taylor . The directing engineers were John Taylor and Sons. The company's bankers, brokers and solicitors were all London-based. On 8 April 1853 Napoleon III issued a decree that re-authorized the Société anonyme des Mines de plomb argentifère et des Fonderies de Pontigibaud. The statutes of

2079-561: The Puy-Saint-Gulmier anthracite concession by decree of 18 March 1907 due to prolonged non-exploitation. The three lead-silver mining concessions in the Pontgibaud district were renounced in 1939. The company decided to expand into processing lead ore from other parts of the world. Land was available on the tidal lower Loire to which lead ore could be brought from Sardinia and coal from Britain. The company acquired an English company with

2156-510: The Romans ). This refers to lead glass as "Jewish glass", perhaps indicating its transmission to Europe. A manuscript preserved in the Biblioteca Marciana , Venice, describes the use of lead oxide in enamels and includes recipes for calcining lead to form the oxide. Lead glass was ideally suited for enamelling vessels and windows owing to its lower working temperature than the forest glass of

2233-498: The Romans. Lead extracted in Roman times may have been used to cover the roof of the Temple of Mercury at the summit of Puy de Dôme , a nearby mountain. Documents from the 8th century onward attest to the mines being worked. In 1554 the lord of Pontgibaud enlarged the mining zone to extend to Roure, les Rosiers, Barbecot and les Combres. At that time mining would have been done by primitive techniques, with hand-powered machinery to hoist up

2310-498: The Sioule river and the neighboring lands in a region that is now very dependent on tourism. As of 2016 work was in progress to restructure the mounds of deposits, surround them by drainage ditches and cover them with meadows. The Pontgibaud-stade and La Brousse sites were secured in 2014. Work was planned for the Roure les Rosiers site in 2016, a 15 hectares (37 acres) site with about 84,700 cubic metres (2,990,000 cu ft) of tailings,

2387-496: The auspices of the Worshipful Company of Glass Sellers of London, Ravenscroft sought to find an alternative to Venetian cristallo . His use of flint as the silica source has led to the term flint glass to describe these crystal glasses, despite his later switch to sand. At first, his glasses tended to crizzle , developing a network of small cracks destroying its transparency, which was eventually overcome by replacing some of

Société des mines et fonderies de Pontgibaud - Misplaced Pages Continue

2464-451: The bank of the river below a cliff. It was connected to the railway and had a private dock on the river. Lead was imported from Tunisia, copper from Canada, zinc from Belgium and aluminum from southeast France. In the early 1950s the plant was delivering about 7,200 tons per year of copper and alloy products, and 2,400 of lead products. Hunting bullets were a significant product, with the factory accounting for 10% of French production. Many of

2541-554: The base of the Combrailles . The deposits include diverse secondary minerals such as arsenopyrite , anglesite , baryte , bournonite , cerussite , chalcopyrite , freibergite , galena , mimetite , pyrite , pyromorphite , quartz , semseyite , sphalerite , stannite , tetrahedrite and wulfenite . Many European museum hold samples of these minerals, collected from the Pontgibaud mines by 19th century mineralogists. The deposits of silver-lead ore are thought to have been worked by

2618-471: The body. Antonio Neri devoted book four of his L’Arte Vetraria ("The Art of Glass-making", 1612) to lead glass. In this first systematic treatise on glass, he again refers to the use of lead glass in enamels, glassware, and for the imitation of precious stones. Christopher Merrett translated this into English in 1662 ( The Art of Glass ), paving the way for the production of English lead crystal glass by George Ravenscroft. George Ravenscroft (1618–1681)

2695-516: The company faced competition from the Cévennes mines. Production began to decline after 1880 and pits were progressively closed. The foundry continued to process minerals from outside the region, then in 1897 was finally closed. In total 68 kilometres (42 mi) of galleries and 2,900 metres (9,500 ft) of shafts had been dug. 50,000 tons of lead were produced and 100 tons of pure silver. The société des mines et fonderies de Pontgibaud lost its title to

2772-458: The company put up several new buildings, inaugurated in 1878, including the lead tower and the big hall (now the media library). On 7 July 1879 the Société des fonderies et laminoirs de Couëron merged with the Société des mines et fonderies de Pontgibaud. The facility had 350 employees in 1879, 555 in 1884 and 1,200 in 1932. After World War II the Couëron plant stopped refining lead ore. In the 1950s

2849-462: The crizzling problem, Ravenscroft was granted the use of a raven's head seal as a guaranty of quality. In 1681, the year of his death, the patent expired and operations quickly developed among several firms, where by 1696 twenty-seven of the eighty-eight glasshouses in England, especially at London and Bristol, were producing flint glass containing 30–35% PbO. At this period, glass was sold by weight, and

2926-455: The customers were in the Nantes region, including the Nantes and Saint-Nazaire naval shipyards, Indret marine engine plant, Donge oil refineries and other industrial plants, but its products were sold throughout France. The factory employed 600 workers and 100 office staff. Up to half the workers lived in housing built by the factory, while others lived in the surrounding country. In 1955 the factory

3003-411: The degree to which the glass separates light into its colors, as in a prism . The increases in refractive index and dispersion significantly increase the amount of reflected light and thus the "fire" in the glass. In cut glass , which has been hand- or machine-cut with facets, the presence of lead also makes the glass softer and easier to cut. Crystal can consist of up to 35% lead, at which point it has

3080-624: The eleventh century high-lead glazes had developed, typically containing 20–40% PbO and 5–12% alkali. These were used throughout Europe and the Near East, especially in Iznik ware , and continue to be used today. Glazes with even-higher lead content occur in Spanish and Italian maiolica , with up to 55% PbO and as low as 3% alkali. Adding lead to the melt allows the formation of tin oxide more readily than in an alkali glaze: tin oxide precipitates into crystals in

3157-423: The glaze as it cools, creating its opacity. The use of lead glaze has several advantages over alkali glazes in addition to their greater optical refractivity. Lead compounds in suspension may be added directly to the ceramic body. Alkali glazes must first be mixed with silica and fritted prior to use, since they are soluble in water, requiring additional labor. A successful glaze must not crawl , or peel away from

Société des mines et fonderies de Pontgibaud - Misplaced Pages Continue

3234-483: The government granted Ireland free trade in glass without taxation. English labour and capital then shifted to Dublin and Belfast, and new glassworks specialising in cut glass were installed in Cork and Waterford . In 1825, the tax was renewed, and gradually the industry declined until the mid-nineteenth century, when the tax was finally repealed. From the 18th century, English lead glass became popular throughout Europe, and

3311-448: The high refractive index caused by the lead content. Ordinary glass has a refractive ( n ) of 1.5, while the addition of lead produces a range up to 1.7 or 1.8. This heightened refractive index also correlates with increased dispersion , which measures the degree to which a medium separates light into its component wavelengths, thus producing a spectrum, just as a prism does. Crystal cutting techniques exploit these properties to create

3388-471: The high content of the heavy metal lead. Lead also raises the density of the glass, being over 7 times as dense as calcium. The density of soda glass is 2.4  g / cm (1.4 oz/cu in) or below, while typical lead crystal has a density of around 3.1 g/cm (1.8 oz/cu in) and high-lead glass can be over 4.0 g/cm (2.3 oz/cu in) or even up to 5.9 g/cm (3.4 oz/cu in). The brilliance of lead crystal relies on

3465-667: The high refractive index which leads to both pronounced Cherenkov radiation and containment of the Cherenkov light by total internal reflection makes lead glass one of the prominent tools for photon detection by means of electromagnetic showers . The high ionic radius of the Pb ion renders it highly immobile in the matrix and hinders the movement of other ions; lead glasses therefore have high electrical resistance, about two orders of magnitude higher than soda–lime glass (10 vs 10 ohm·cm, DC at 250 °C or 482 °F). Lead-containing glass

3542-645: The largest of the three chimneys, 50 metres (160 ft) high, and a few buildings still remain. A 2.7 kilometres (1.7 mi) diversion canal from the Sioule, which powered the pumps and hoists of Barbecot. and Pranal, is still visible. The four sites for crushing and washing the minerals left about 300,000 cubic metres (11,000,000 cu ft) of tailings . These contain high levels of lead , arsenic , cadmium and zinc . The deposits contain no organic material, have steep slopes and have high metallic content, all of which prevent growth of vegetation. They are subject to strong erosion by water and wind, which impacts

3619-611: The last 10,000 years, these central mountains are separated from the Alps by a deep north–south cleft created by the Rhône river and known in French as the sillon rhodanien (literally "Rhône furrow"). The region was a barrier to transport within France until the opening of the A75 motorway , which not only made north–south travel easier but also opened access to the massif itself. The Massif Central

3696-437: The late 11th-early 12th century, Schedula Diversarum Artium ( List of Sundry Crafts ), the author known as " Theophilus Presbyter " describes its use as imitation gemstone, and the title of a lost chapter of the work mentions the use of lead in glass. The 12–13th century pseudonymous "Heraclius" details the manufacture of lead enamel and its use for window painting in his De coloribus et artibus Romanorum ( Of Hues and Crafts of

3773-502: The lead compound with silica, which is then placed in suspension and applied directly. The third method involves fritting the lead compound with silica, powdering the mixture, and suspending and applying it. The method used on a particular vessel may be deduced by analysing the interaction layer between the glaze and the ceramic body microscopically. Tin-opacified glazes appear in Iraq in the eighth century AD. Originally containing 1–2% PbO; by

3850-593: The manufacture of perfectly clear, flawless objects. When tapped, lead crystal makes a ringing sound, unlike ordinary glasses. The wine glasses were always valued also for their "ring" made by the clinking glasses . The sound was better when large quantity of the lead oxide was present in the glassmaking material, like in the British and Irish wine glasses of the 17th-19th centuries with their "rich bell-notes of F and G sharp ". Consumers still rely on this property to distinguish it from cheaper glasses. Emil Deeg had published

3927-412: The molten glass gives lead crystal a much higher index of refraction than normal glass, and consequently much greater "sparkle" by increasing specular reflection and the range of angles of total internal reflection . Ordinary glass has a refractive index of n = 1.5; the addition of lead produces an index of refraction of up to 1.7. This higher refractive index also raises the correlated dispersion ,

SECTION 50

#1733084756449

4004-427: The money needed to build a 18 kilometres (11 mi) adit to drain the mines, a huge project. Pallu visited England in 1845 to study mining techniques and to look for investors. He asked the consulting firm John Taylor and Sons to undertake a study of the Pontgibaud mines. The consultant's report was favorable, but recommended a complete reorganization of the operation. The Société des mines et fonderies de Pontgibaud

4081-414: The most sparkle. Makers of lead crystal objects include: Several studies have demonstrated that serving food or drink in glassware containing lead oxide can cause lead to leach into the contents, even when the glassware has not been used for storage. Due to an inability to "indicate a threshold for the key effects of lead," a 2011 World Health Organization committee on food additives "concluded that it

4158-663: The ore, crush it and sort out the mineral-rich portions. A member of the Moré family, a musketeer of Louis XV of France (1710–74), bought the estate of Pontgibaud in 1756, including an ancient keep and a more modern château built in the time of Louis XIII (1601–43). He was made the Comte de Pontgibaud, taking the name "Moré de Pontgibaud". Between 1828 and 1830 Count Moré de Pontgibaud obtained concessions to open mines near his chateau. The mines were successful and soon employed 200 miners underground and 600 workers above ground. The central jury of

4235-432: The original lead foundry was demolished and replaced by more modern buildings. However, the company expanded the range of its products, adding aluminum to lead, copper and brass. By this time the Couëron factory was the company's only property in France other than depots and commercial offices. It was the 4th largest producer of non-ferrous metal products in France, occupying a site 950 by 50 metres (3,120 by 160 ft) along

4312-479: The potash flux with lead oxide to the melt, up to 30%. Crizzling results from the destruction of the glass network by an excess of alkali, and may be caused by excess humidity as well as inherent defects in glass composition. He was granted a protective patent in 1673, where production moved from his glasshouse in the precinct of the Savoy , London, to the seclusion of Henley-on-Thames . In 1676, having apparently overcome

4389-444: The pottery surface upon cooling, leaving areas of unglazed ceramic. Lead reduces this risk by reducing the surface tension of the glaze. It must not craze, forming a network of cracks, caused when the thermal contraction of the glaze and the ceramic body do not match properly. Ideally, the glaze contraction should be 5–15% less than the body contraction, as glazes are stronger under compression than under tension. A high-lead glaze has

4466-449: The present day. In China, similar glazes were used from the twelfth century for colored enamels on stoneware, and on porcelain from the fourteenth century. These could be applied in three different ways. Lead could be added directly to a ceramic body in the form of a lead compound in suspension, either from galena (PbS), red lead (Pb 3 O 4 ), white lead (2PbCO 3 ·Pb(OH) 2 ), or lead oxide (PbO). The second method involves mixing

4543-460: The result of imported English workers. Imitating lead-crystal à la façon d’Angleterre presented technical difficulties, as the best results were obtained with covered pots in a coal-fired furnace, a particularly English process requiring specialised cone-furnaces. Towards the end of the eighteenth century, lead-crystal glass was being produced in France, Hungary, Germany, and Norway. By 1800, Irish lead crystal had overtaken lime-potash glasses on

4620-542: The richest in Europe. In 1857 the Pontgibaud smelter produced 1,919 kilograms (4,231 lb) of silver and 562,000 kilograms (1,239,000 lb) of lead. In 1871 alone 5,255 tons of ore were extracted. The mines employed 1,500 people, not counting related trades, and were the largest employer in the region. Miners worked 12-hour shifts and earned from 1.25 to 2 francs a day. At the time, bread cost 32 centimes. The company created an insurance and providence fund, and miners received

4697-444: The rock crystal ( quartz ) imitated by Murano glassmakers. This naming convention has been maintained to the present day to describe decorative holloware . Lead crystal glassware was formerly used to store and serve drinks, but due to the health risks of lead , this has become rare. One alternative material is modern crystal glass, in which barium oxide , zinc oxide , or potassium oxide are employed instead of lead oxide. In

SECTION 60

#1733084756449

4774-588: The site was sold to Lambert Manufil. The lead tower was declared a historical monument in 1993. Émile Paraf joined the Société des forges de Châtillon-Commentry-Neuves-Maisons after the Franco-Prussian War of 1870, and also became head of the Mines et Fonderies de Pontgibaud, which prospered under his administration. He was later active in various other mining and metallurgy companies and industry organizations. Paraf

4851-822: The society were registered by Alphonse Pallu, manager, Frédéric-Adolphe Marcuard, banker, and Paul Bontoux, proprietor. The society, with headquarters in Paris, had a term of 99 years. The property included the Barbecot, Combres, Roure and Puy-Saint-Gulmier concessions, the crushing and washing facilities at Barbecot and Rosiers, the foundries of Pontigibaud and miscellaneous machinery and buildings. 10,000 shares were issued to 76 individuals or organizations. The larger shareholders were Adolphe Marcuard & cie (2,800), Charles Morrison (1,000), William Thompson (1,000), John Taylor et Sons (1,000), Paul Bontoux (529), Octavius Ommaney (500) and D. Forbes-Cambell (500). The Count of Pontgibaud had 161 shares and Alphonse Pallu had 75 shares. Pontgibaud

4928-682: The south and in the east ( Cévennes ) dominating the valley of the Rhône and the plains of Languedoc and, by contrast, the less elevated region of Limousin in the northwest. These tectonic movements created faults and may be at the origin of the volcanism in the massif (but the hypothesis is not proved yet). In fact, above the crystalline foundation, one can observe many volcanoes of many different types and ages: volcanic plateaus ( Aubrac , Cézallier ), stratovolcanoes ( Mounts of Cantal , Monts Dore ), and small, very recent monogenic volcanoes ( Chaîne des Puys , Vivarais ). The entire region contains

5005-752: The south, one remarkable region is made up of features called Causses in French and consists of raised limestone plateaus cut by very deep canyons. The most famous of them is the Gorges du Tarn (Tarn Canyon). Mountain ranges, with notable individual mountains, are (roughly north to south): The following departments are generally considered as part of the Massif Central : Allier , Ardèche , Aude , Aveyron , Cantal , Corrèze , Creuse , Gard , Haute-Garonne , Haute-Loire , Haute-Vienne , Hérault , Loire , Lot , Lozère , Puy-de-Dôme , Rhône , Saône-et-Loire , Tarn , and Tarn-et-Garonne ; these form parts of

5082-492: The typical forms were rather heavy and solid with minimal decoration. Such was its success on the international market, however, that in 1746, the British Government imposed a lucrative tax by weight. Rather than drastically reduce the lead content of their glass, manufacturers responded by creating highly decorated, smaller, more delicate forms, often with hollow stems, known to collectors today as Excise glasses . In 1780,

5159-492: The world's third-largest seed producer and cheese-producing industries that export to the world such as Cantal and Roquefort ). On the agricultural level, the Limagne plain is dominated by major cereal crops, but in the mountains, it is mainly livestock farming that predominates: cattle farming in the west for meat and milk (Cantal cheese), sheep farming in the south on the limestone plateaus (Roquefort cheese). Finally, tourism

5236-510: Was a limited company authorized by decree in 1847. It took over the concession, buildings and all other physical assets of Pallu et Compagnie. The Puy-Saint-Gulmier anthracite concession was granted to the company by decree of 7 August 1850. The company, registered as a Paris-based société anonyme , was floated in London in 1852. The four French directors were Alphonse Pallu, the Count of Pontgibaud and

5313-418: Was at the center of a dozen sites extending for 10 kilometres (6.2 mi) in a north-south direction. The foundry at Pontgibaud processed ore from the nearby Pranal, Barbecot, Roure les Rosiers, La Miouse and Villevieille mines. The lead was used for crystal , plumbing, ceramics and paint, while the silver was used for coins. The mines yielded 5 kilograms (11 lb) of silver per ton of lead, and were some of

5390-537: Was certainly not used as the primary fluxing agent in ancient glasses. Lead glass also occurs in Han-period China (206 BC – 220 AD). There, it was cast to imitate jade , both for ritual objects such as big and small figures, as well as jewellery and a limited range of vessels. Since glass first occurs at such a late date in China, it is thought that the technology was brought along the Silk Road by glassworkers from

5467-639: Was demolished. The restoration of the Château-Dauphin included modern features such as electricity and cold water taps on each floor. Later renovations added further comforts such as hot water and bathrooms. As of 2017 the Germiny family still lived in the Château-Dauphin in Pontgibaud. The Musée de la Mine d'argent in three rooms of the Château Dauphin covers mining history in the Sioule valley, particularly

5544-694: Was found to add up to 14.5 μg of lead from drinking a 350ml cola beverage. The amount of lead released into a food or drink increases with the amount of time it stays in the vessel. In a study performed at North Carolina State University , the amount of lead migration was measured for port wine stored in lead crystal decanters . After two days, lead levels were 89 μg/L (micrograms per liter). After four months, lead levels were between 2,000 and 5,000 μg/L. White wine doubled its lead content within an hour of storage and tripled it within four hours. Some brandy stored in lead crystal for over five years had lead levels around 20,000 μg/L. Lead leaching from

5621-482: Was ideally suited to the new taste for wheel-cut glass decoration perfected on the Continent owing to its relatively soft properties. In Holland, local engraving masters such as David Wolff and Frans Greenwood stippled imported English glassware, a style that remained popular through the eighteenth century. Such was its popularity in Holland that the first Continental production of lead-crystal glass began there, probably as

5698-511: Was not possible to establish a new PTWI (provisional tolerable daily intake) that would be considered health protective." The amount of lead released from lead glass increases with the acidity of the substance being served. Vinegar, for example, has been shown to cause more rapid leaching compared to white wine, as vinegar is more acidic. Citrus juices and other acidic drinks leach lead from crystal as effectively as alcoholic beverages. Daily usage of lead crystalware (without longer-term storage)

5775-500: Was responsible for the merger of the Société des Mines et Fonderies de Pontgibaud with the Fonderies et Laminoirs de Couëron. He directed the new company until his death in 1924. Mounds of infertile yellow spill dotted the landscape around Pontgibaud for many years after mining ended. A century after the mines were closed there remained nearly 60 traces of open and dangerous shafts and galleries, which were made safe in 2009. At Pontgibaud

5852-412: Was taken over by CFM ( Compagnie française des métaux ), and 101 workers were laid off. The lead tower ceased operation in 1958. In 1962 the facility became owned by Tréfimétaux . New workshops were built, but the economy was struggling. The number of employees had declined to 550 in 1965 and 350 in 1975. Around 1986 the factory became Métayer-Noël. It had 160 employees in 1988, when it closed down. In 1992

5929-437: Was the first to produce clear lead crystal glassware on an industrial scale. The son of a merchant with close ties to Venice, Ravenscroft had the cultural and financial resources necessary to revolutionise the glass trade, setting the basis from which England overtook Venice and Bohemia as the centre of the glass industry in the eighteenth and nineteenth centuries. With the aid of Venetian glassmakers, especially da Costa, and under

#448551