Grozon coal and saltworks: Difference between revisions

| area_served = [[Grozon]] , [[France]]

The '''The Grozon collieries and saltworks''' are [[coal]] and [[Halite|rocksalt]] [[Mining|mines]] located in the [[Keuperian basin]], in the [[Jura (department)|Jura]] [[Departments of France|department]] of [[Bourgogne-Franche-Comté]], in eastern [[France]]. They were mined in the communes of [[Grozon]] and [[Tourmont]] from 1845 to 1944 for the coal and from the 6th to the 20th century for the salt, after an initial period of mining in the [[Neolithic]] period and during the [[Ancient history]]. The use of coal on site to [[Evaporation|evaporate]] the [[brine]] enabled the '''Jura Mining Company''' (which only owned this saltworks) to reduce the cost of salt.

The 19th-century saltworks buildings were converted into a nursery school, village hall and housing at the end of the 20th century. The remains of the [[Early Middle Ages|early medieval]] saltworks were uncovered during a [[rescue archaeology]] at the end of 2014, and are now considered unique in [[France]].

The [[Bituminous coal|black coal]] and [[halite]] [[Mining|deposits]] mined are intermingled in the [[Haute-Saône Keuperian coalfield]]. This basin consists of alternating layers of [[sandstone]], iridescent [[marl]] and [[gypsum]] [[Dolomite (rock)|dolomite]]. The salt layer lies at a depth of 86 meters, is 6.5 meters thick, and the material extracted by blasting yields 87% [[Salt|pure salt]].<ref name=":0" />.

Traces of salt extraction dating back to the [[Neolithic]] period have been found in the commune. First extraction took place around [[30th century BC|3900-3540 BC]]. As the region became more settled, salt mining intensified in the 13th century BC.<ref>{{Cite book |lastlast1=Grassias |firstfirst1=Yvan |author-link= |url= |title=De pierre et de sel : Les salines de Salins-les-Bains |last2=Markarian |first2=Philippe |last3=Pétrequin |first3=Pierre |last4=Weller |first4=Olivier |publisher=Musées des techniques et cultures comtoises |year=2006 |isbn=2911484126 |pages=44 |language=FR}}</ref>.

At that time, from the Neolithic to the Roman period, [[brine]] [[evaporation]] was carried out without containers or infrastructure, but on the ground on a pyre set up near the salt springs. Layers of [[ash]] and [[charcoal]] accumulated over a distance of some ten meters were observed in [[Salins-les-Bains]], [[Grozon]] and [[Lons-le-Saunier]] during archaeological research carried out between 1996 and 2001. These remains have been dated to 6,000 years ago. Grozon offers better research prospects than Salin or Lons, which are located in an urban context.<ref>{{Harvtxt|Pierre Pétrequin|Olivier Weller|2008|pp=258-265258–265}}</ref> context.

The discrete exploitation of the Neolithic period intensified during the [[Bronze Age]], with a first peak in production around [[15th century BC|1400-1500 BC]], accompanied by [[population growth]]. The second production peak occurred at the beginning of the Iron Age. After the 4th century BC., Grozon became, along with Lons-le-Saunier, one of the two main salt production sites of the [[Sequani]], and remained so until [[Gallic Wars]], when Sequani [[Salting (food)|salt products]] were particularly in demand on the markets of [[Rome]].<ref>{{Harvtxt|Pierre Pétrequin|Olivier Weller|2008|ppp=265265–266}}</ref>. In order to promote Roman salt, the [[Empire]] built a monumental sanctuary over the spring and prevented any exploitation.<ref>{{Harvtxt|Pierre Pétrequin|Olivier Weller|2008|ppp=265-266}}</ref>.

Grozon's ash layers were exploited in the 19th century as fertilizer for [[Bresse]] farms.<ref>{{Harvtxt|Alexa Dufresse|Émilie Ghautier|2002|p=247}}</ref> farms. The evaporation of salt consumed large quantities of wood at all times, leading to extensive forest [[Clearing (geography)|clearance]]. The increasing scarcity of certain species as the activity intensifies shows that [[hornbeam]], [[beech]] and especially [[oak]] are used as fuel.<ref>{{Harvtxt|Alexa Dufresse|Émilie Ghautier|2002|p=255}}</ref>.

An ancient [[Sea salt|saltworks]] was in operation in [[Grozon]] in the 6th century, mentioned in a donation text dated 722.<ref name=":12">{{CitewebCite web |year=2014 |title=Une saline dude hautl'époque Moyen Âgemérovingienne découverte surà un chantierGrozon dans le Jura |url=https://france3-regionswww.francetvinfofrancebleu.fr/franche-comteloisirs/juraevenements/une-saline-dude-hautl-moyenepoque-agemerovingienne-decouverte-sur-un-chantiergrozon-dans-le-jura-572964.html1413399626 |archive-url= |website=France 3Bleu Franche-ComtéBesançon |language=FR}}</ref><ref name=":21">{{CitewebCite web |year=2014 |title=Une saline dedu l'époquehaut mérovingienneMoyen Âge découverte àsur Grozonun chantier dans le Jura |url=https://wwwfrance3-regions.francebleufrancetvinfo.fr/loisirsfranche-comte/evenementsjura/une-saline-dedu-lhaut-epoquemoyen-merovingienneage-decouverte-grozonsur-un-chantier-dans-le-jura-1413399626 |archive-url=572964.html |website=France Bleu3 BesançonFranche-Comté |language=FR}}</ref>. Ownership of the saltworks changed regularly between lords and local religious authorities. In 906, it was acquired by the [[Flavigny Abbey|Abbey of Flavigny]], then by [[Hugues Ixxxx|Hugues I]], [[Archbishop of Besançonxx|Archbishop of Besançon]] in 1053. Thirty years later, it became the property of [[Rosières Abbey]]. The buildings were burnt down and the spring blocked after a treaty of June 23, 1369, which obliged [[Margaret I, Countess of Burgundy|Margaret I Countess of Burgundy]], who had inherited the property, to destroy the saltworks so that the [[Salins saltworks]] would be the only one to produce in the [[Roman Catholic Archdiocese of Besançon|Archdiocese of Besançon]]. In 1854<ref name=":0" />, ruins of the walls covered with earth, coal, ash and old tiles remained.<ref name=":0" />

TheIn September 2014, the remains of five buildings of different architectural styles were discovered over an area of 600 m2square in September 2014meters during an archaeological survey carried out by the [[Direction régionale des affaires culturelles|Direction Régionale des Affaires Culturelles]] (DRAC,by its French acronym) and the [[Institut National de Recherches Archéologiques Préventives]] (INRAP, by its French acronym). [[Foundation (engineering)|Foundations]] of wooden buildings, andas well as the base of thestone walls measuring 50 cm-centimeters thick, and 1.5-meter-high stonemeters wallshigh offrom the quadrangular evaporation building, were uncovered, along with [[Ceramic|ceramics]]. [[Archaeology|Archaeologists]] believe that these remains are unique in [[France]], and that the presence of a masonry building (usually reserved for a [[place of worship]] in this period) calls into question historical knowledge of [[Early Middle Ages|early medieval]] saltworks infrastructures. The wooden elements are preserved by the presence of the [[phreatic zone]]. These remains were reburied to preserve them at the end of the excavation on November 3. A [[pavilion]] was built over them in 2015.<ref name=":1" /><ref name=":2" /><ref>{{CitewebCite web |year=2014 |title=Franche-Comté,Grozon (Jura, Grozon, rue des Salines : nouveaux indices de la saline du haut Moyen Âge : rapport de diagnostic) |url=httphttps://doliaagglocene.inraphuma-num.fr/floranotices-de-sites/ark:jura/12345grozon-jura/0131267 |website=dolia.inrap.frAggloCenE |language=FR}}</ref>.

The Compagnie des Mines du Jura was created in 1840 with a capital of one million francs divided into 2,000 [[Share (finance)|shares]]<ref name=":0" /> and was granted the Grozon concession by [[Decree|royal decree]] on April 12, 1845.<ref name=":0" /> [[Salt mining]] began in 1852 with [[extraction shafts]] and [[adit]] mining. However, this method was replaced by a more cost-effective system of drawing [[brine]] from three boreholes drilled directly from the eight-stove evaporation plant built by engineers Delize, Thomas and Boucard between 1853 and 1854. Commissioning of the plant was authorized on February 3, 1855, and was powered by a [[steam engine]]. The evaporation workshop collapsed in 1873, and was quickly rebuilt. In 1875, the saltworks were bought by the [[Société des anciennes Salines domaniales de l'Est]], which led to the dissolution of the Compagnie des Mines du Jura. Two years later, the company relaunched a well dug in 1840, but which had remained unused.<ref name=":3">{{CitewebCite web |title=Saline de Grozon |url=https://www.pop.culture.gouv.fr/notice/merimee/IA39000110 |website=base Mérimée, Ministère Français de la Culture. |language=FR}}</ref>.

Annual salt production rose from 1,200 tons in 1864 with twelve workers, to 3,000 tons in 1875, before dropping to 960 tons in 1884 and ceasing the following year. It employed five workers in 1882. In 1888, the Grozon salt concession merged with the [[Montmorot concession]].The boreholes were reinforced between 1891 and 1896, and a fourth borehole was dug. The concession was revoked by decree in 1901, but the following year the decree was rescinded. The operation was relaunched in 1918; the following year, four new pans were installed, producing 2,855 tons of salt in the course of the year.<ref name=":3" />.

A saltworks store and workshop were demolished in the 1960s. At the beginning of the 21st century, the buildings housing the living quarters, offices, machine room and the [[extraction machine]] building housing the brine pumping holes remained. All these buildings were converted into a village hall, nursery school, housing and garage around 1980. On December 18, 2008, the saltworks were included in the [[General inventory of cultural heritage]].<ref name=":3" />. <gallery mode="packed" heights="100">

The deposit, which is mined in a “recumbent bed”,<ref name=":0" />, consists of a single layer varying in thickness from 40 to 80 cmcentimeters. The [[Bituminous coal|coal]] is very dry, consisting of 73.21% [[carbon]] and 3.75% [[ash]]. It is very brittle, requiring the use of formwork in the galleries. It is of poor quality, even after washing, burns poorly due to its low calorific value and leaves a lot of ash. All these factors led to the cessation of operations.<ref>{{CitebookCite book |last=Ogérien |first=Grenier |url=https://books.google.frcom/books?id=IeTE2jz4YgQC&dqq=Grozon+houille&hl=fr&source=gbs_navlinks_s |title=Histoire naturelle du Jura et des départements voisins |publisher=Masson |year=1865 |pages=327-329327–329 |language=FR}}</ref>.

Between 1942 and 1944, the concession was taken over by the [[Montmorot and Montaigu saltworks|Montmorot and Montaigu saltwork]],<ref name=":3" />, and two [[Chutesxx|chutes]] were dug, one to the north and the other to the south of the valley. The coal beds are disturbed by numerous faults. The carbon is blasted and sent by [[Rail transport|rail]] to [[Villeneuve-d'Ascq|Villeneuve]] and [[Montmorot]], as well as to the [[Grenoble]] [[coal gas]] plant.<ref>{{Harvtxt|R. Dormois|J.Ricours|1943|pp=17-2017–20}}</ref> [[coal gas]] plant.<gallery mode="packed">

* {{CitebookCite book |lastlast1=Pétrequin |firstfirst1=Pierre |url=https://www.academia.edu/11014279/PETREQUIN_P._et_WELLER_O._2008.-_L_exploitation_pr%C3%A9historique_des_sources_sal%C3%A9es_dans_le_Jura_fran%C3%A7ais._Application_et_critiques_d_un_mod%C3%A8le_pr%C3%A9dictif_Besan%C3%A7on_Presses_Universitaires_de_Franche-Comt%C3%A9_255-279 |title=Sel, eau et forêt d'hier à aujourd'hui |last2=Weller |first2=Olivier |publisher=Presses Univ. Franche-Comté |year=2008 |isbn=9782848672304 |series=Les Cahiers de la MHSE Ledoux |pages=256-279256–279 |language=FR}}

* {{CitebookCite journal |lastlast1=Dufresse |firstfirst1=Alexa |url=https://www.academia.edu/3798711/Exploitation_des_sources_sal%C3%A9es_en_Franche-Comt%C3%A9_impact_sur_l_espace_forestier_du_N%C3%A9olithique_%C3%A0_la_p%C3%A9riode_m%C3%A9di%C3%A9vale._Dufraisse_A._et_Gauthier_E |title=Exploitation des sources salées en Franche-Comté : impact sur l’espacel'espace forestier du Néolithique à la période médiévale |last2=Ghautier |first2=Émilie |journal=Archéologie du Sel: Techniques et Sociétés Édité Par O. Weller, 2002 Internationale Archäologie, Astk 3 Colloque 12.2, Xive Congrès Uispp, Liège, Septembre 2001 |year=2002 |pages=243-257243–257 |language=FR}}

* {{CitebookCite book |lastlast1=Dormois |firstfirst1=R. |url=http://infoterre.brgm.fr/rapports/BRGG-A0031.pdf |title=Houille triasique sur le versant N.O. du Jura |last2=Ricours |first2=J. |publisher=Bureau de recherches géologiques et minières (BRGM) |year=1943 |language=FR}}

* {{CitebookCite book |last=Rousset |first=A. |url=http://www.cegfc.net/www/sections/fiches-communes/jura/39263/grozon_historique.pdf |title=Extrait du Dictionnaire Géographique, Historique et Statistique des communes de la Franche-Comté |publisher=Grozon (39), t. III, cegfc.net |year=1854 |language=FR}}