DISCOVERY AND MINING HISTORY OF THE "CALAMINE" IN SW SARDINIA (ITALY)
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J. E. Ortiz, O. Puche, I. Rábano and L. F. Mazadiego (eds.) History of Research in Mineral Resources. Cuadernos del Museo Geominero, 13.
Instituto Geológico y Minero de España, Madrid. ISBN 978-84-7840-856-6
© Instituto Geológico y Minero de España 2011
Discovery and mining history of the “calamine“
in SW Sardinia (Italy)
Maria Boni
Dipartimento Scienze della Terra, Università di Napoli Federico II, Via Mezzocannone, 8. 80134 Napoli, Italy. boni@unina.it
Abstract. In year 1865 the French-Belgian engineer Jean Eyquem discovered the “Calamine” ores
(carbonate-hosted Zn(Pb) mineralizations of the Nonsulfide type) in a coastal area of southwest
Sardinia. This discovery changed totally both the economic and social life in Sardinia, converting
Italy in one of the main producers for the zinc commodity. The Companies working the Calamine
ores were French (Malfidano), Belgian (Vieille Montagne) and then Italian (Monteponi). The
most important Calamine mining districts were: Buggerru-Planu Sartu, San Benedetto-Baueddu,
San Giovanni-Seddas Moddizzis-Campo Pisano and Monteponi-Agruxiau. The main difference
between the deposits was their iron content. In the Buggerru area, the community’s life and
customs were so heavily influenced by floods of innovations related to mining activity, that the
town was nicknamed „small Paris“. Also in the Monteponi area, near Iglesias, great amounts of
“Calamine” were discovered before the turn of the century, and actively exploited. In the latter
area, the most modern exploitation and treatment methods were applied to the Calamine ore,
ranging from several types of furnaces, to the electrolytic process. In 1926 was inaugurated at
Monteponi the electrolytic plant for the low-grade ore. This plant, one of the best in Europe for
the time, consisted of 168 cells to be filled with the acid solution and 20 cathodic sheets, where
the zinc precipitated and was then stripped. At this point, Sardinia was able to export Zn metal
and not only the ore concentrate.
1. Introduction
The “Calamines” are carbonate-hosted Zn(Pb) ores of the Nonsulfide type. They derive from weathering of pri-
mary Zn(Pb)-sulfide concentrations, eventually followed by precipitation of newly formed Zn- and Pb-minerals,
when the metal-carrying solutions are buffered by the carbonate host rocks (Large, 2001).
In 1865 the French-Belgian engineer Jean Eyquem discovered the “Calamine” ores in a coastal area of
southwest Sardinia, north of the old mining village of Fluminimaggiore. This discovery changed totally both the
economic and social life in Sardinia, converting Italy at the same time in one of the main producers for the zinc
commodity (Sella, 1871). The nonsulfide „Calamine” ores were exploited in the island until the 1980s.
The SW Sardinia mining district (Fig. 1) is one of the classical areas where primary carbonate-hosted Zn-
Pb sulfide ores are capped by a relatively thick secondary oxidation zone, containing Zn (hydroxy) carbonates
(smithsonite and hydrozincite) and silicates (hemimorphite) (Boni et al., 2003). The mineralogy of these ores
is generally complex, and comprises not only the above-mentioned zinc minerals, but also cerussite (PbCO3)
and anglesite (PbSO4), as well as several, fairly exotic species, dear to mineral collectors (Stara et al., 1996).
25Maria Boni
The nonsulfide ore grade was highly variable throughout the mining district, ranging from a few percent of
combined Zn-Pb to more than 30 percent in the areas where the alteration profile resulted in a complete re-
placement of the sulfides by secondary carbonates.
A thorough understanding of the mineralogy, but also of the petrographic associations of the ore and
host rock has always been a “must” in exploration targeting and feasibility studies of the Sardic “Calamine”
deposits, because of its impact on processing and metallurgy, which was steadily evolving through the eighty
years of mining history.
Figure 1. Geological sketch map of the Iglesiente mining district, with the location of the sampled sites (from Boni et
al. 2003, mod.). Abbreviations: 1 - overthrust; 2 - normal fault; 3 - Cenozoic; 4 - Mesozoic; 5 - Variscan granites; 6 -
Palaeozoic (allochthonous); 7 - Ordovician to Devonian succession; 8 - Iglesias Group (Middle Cambrian-Lower Ordovician);
9 - Gonnesa Group (Lower Cambrian); 10 - Nebida Group (Lower Cambrian).
26Discovery and mining history of the “calamine“ in SW Sardinia (Italy)
2. The “calamine” mining centres in SW Sardinia
Buggerru-Planu Sartu
After the discovery of the “Calamine” deposits along the coastal region from S. Nicolò to Masua, the „Societè
Anonyme des Mines de Malfidano“ was founded (Fig. 2A), which led the way to an intensive exploitation of
the entire region (Fig. 2B, 2C). The mineral boom brought with it the development of a large village that shortly
turned into a town, named Buggerru, whose population reached 12,000 inhabitants at the beginning of the
twentieth century. The community’s life and customs were so heavily influenced by floods of innovations, that
the town was nicknamed „small Paris“. In the same area, also other mining villages were established, such as
Planu Sartu (1867), on the peneplane southwest of the Buggerru village.
During the big economic boom, which followed the first discoveries, also the family of the painter Amedeo
Modigliani, which had the concession for producing charcoal in Sardinia, had applied for a permit to exploit
the “Calamine” and, having failed, tried to mine them illegally, this causing many legal problems with the
“Societè Malfidano”.
The quality of the ore was exceedingly good, due to the primary nature of the limestone-hosted sulfides,
which contained high-grade sphalerite, less galena and even less pyrite.
Three plants were successively built in Buggerru for preliminary ore treatment: the first (1866) was called
Buggerru; the second (1870) took the name Lamarmora, and the third one (1890), called Malfidano, operated
until the final closure of the mine in year 1979. However, at that time it was not possible to carry out in Sardinia
the complete processing, to obtain the zinc metal. For this reason, the enriched, and generally also roasted ore,
was transported by small boats (Fig. 2D, 2E) to the port of the San Pietro island further south along the coast,
and from there exported by ship (Fig. 2F) to the smelting centres in France and Belgium.
San Benedetto-Baueddu
The “Calamine” were extensively exploited also in other areas of SW Sardinia. The Belgian Vieille Montaigne
Company was active around the village of San Benedetto, north of Iglesias and in the locality of Baueddu. In
both deposits the nonsulfide concentrations were Fe-rich, due to the high pyrite content of the primary ore
(massive sulfides), and the host rocks exceedingly brittle (fractured dolomites). For this reason only an opencast
mining was considered economic, and of course, when reaching the water table, the exploitation had to be
stopped.
Seddas Moddizzis-San Giovanni-Campo Pisano
At the beginning of the twentieth century rich Calamine concentrations were found also in the southern limb of
the Iglesias syncline: the major deposits were grouped around the locality of Seddas Moddizzis, but interesting
deposits occurred also on the top horizons of the San Giovanni mine (better known for its argentiferous
galena), and at Campo Pisano. The latter Calamines were iron-rich, due to the high content of pyrite in the
primary ores.
On September 1868 a group of local entrepreneurs and owners constituted the Company of Seddas Mod-
dizzis, whose purpose was to explore a large territory south of Mount San Giovanni (Fadda, 1997; Mezzolani
& Simoncini, 1993). The company got the claim on June 1870, for an area of only 177 hectares. In the first
years, few miners worked the Calamine rejected in the preceding works that were concerned only with lead and
27Maria Boni
Figure 2. A. Letter (July 1879) from Mr G. Castanier of
the Societé Malfidano at Buggerru to the Eng. Testore in
Iglesias, concerning the advancing stage of the drainage
“Gallerie Lucien”; B. The Malfidano open pit in Buggerru
(current status); C. The Planu Sartu open pit on the
Buggerru peneplane (current status); D. Buggerru: the
“paranze” (small boats) used for transporting the Calamine
ore; E. San Pietro island: the “paranze” in the harbour;
F. San Pietro island: a ship for Calamine ore transport to
European destinations.
28Discovery and mining history of the “calamine“ in SW Sardinia (Italy)
Figure 3. A. View of the Monteponi mine at the beginning of the twentieth century; B. The Cungiaus open pit at the top of
the Monteponi hill (current status); C. Underground adits and beginning of the open pit at Cungiaus (1911); D. Monteponi:
open pit workings in the Discarica Moreschini (1905); E. Waste heaps (Discarica Moreschini) at the Monteponi mine. On
the left side the furnaces for Calamine roasting (1905); F. Monteponi mine: the chemical laboratory (1905); G. Monteponi:
waste heaps “Fanghi Rossi” (current status); H. Funtanamare: drainage channel Umberto I of the Monteponi mine (current
status); I. Monteponi mine: furnaces for calamine roasting (current
29 status).Maria Boni
silver minerals. The turning point coincided with the arrival at Seddas, on 1885, of the engineer Asproni, that
constructed a new road fit to the transit of the carts and two calcination furnaces, and obtained in 1930 also
the perpetual claim of the mine. During few years more than 100 thousand tons of calamine were extracted at
Seddas Moddizzis from the Ciccilloni and Belgrano trenches and from the Santa Barbara gallery. The mineral
was processed entirely locally, in a plant built in 1893.
Around the fifties, the Company of Monteponi acquired the mine, by the acquisition of the shares of the
Asproni heirs, and in the last years of its activity the mine of Seddas Moddizis was included in the big system
that gravitated around the Campo Pisano mining complex.
Monteponi
Also in the Monteponi area, near the old mining town of Iglesias, great amounts of “Calamine” were discovered
before the turn of the century, and actively exploited through small adits and quarries, the Santa Barbara shaft
and the Is Cungiaus open pit, one of the deepest known in the island (Fig. 3A, 3B). Several waste heaps were
accumulated because of the “Calamine” exploitation and treatment (Fig. 3D, 3E). Some of them (the “Fanghi
Rossi”, Ardau & Runeddu, 2001) (Fig. 3G), one of the marking characteristics of the Iglesias landscape, contain
still more than 8% zinc.
The Monteponi Company built also (1870) a small private railway to transport the ore mineral to the har-
bour village of Porto Vesme. At the same time the difficult problem of draining the lower levels of the mine was
solved with the installation of pumps at several depths in the Quintino Sella shaft (1872-1876), and with the
construction of the drainage gallery Umberto I (Fig. 3H), which started in 1880 and was terminated in 1889
(4,250 m). The energy supply to Monteponi was partly assured by the acquisition of a lignite mine from the
Sulcis basin nearby (Rolandi, 1971).
A preliminary enrichment plant, the “Laveria Calamine” (Fig. 4A), was built at Monteponi with a potential
to treat at least hundred tonn/day of bulk ore, followed by another plant at Seddas Moddizzis. Also several
other metallurgical plants were set for the calcination of the “Calamine”, in vertical and Oxland furnaces to
produce ZnO (Fig. 3I). In fact, it was economically much more convenient to sell the already roasted “Cala-
mine”, instead of the just concentrated ore. In a later stage another calcination plant, which used the Waelz
system rotary furnaces, was built to extract zinc from the “Calamine” and from the older tailings, but this
system was never a big success.
In 1926 was inaugurated at Monteponi by the engineer F. Sartori the electrolytic plant for the low-grade
ore (mainly the Campo Pisano Calamine), which could not be treated mechanically (Rolandi, 1971). This plant
(Fig. 4B, 4C, 4D), one of the best in Europe for that time, consisted of 168 cells to be filled with the acid solu-
tion and 20 cathodic sheets, where the zinc precipitated and was then stripped from. In connection with the
electrolytic cells, also a plant for the production of sulphuric acid, essential for the electrolytic process, was built
at Monteponi in 1928. At this point, Sardinia was able to export Zn metal and not only the ore concentrate.
All the buildings related to the successive steps of mining activity were perfectly visible (some of them
still functioning) at Monteponi in the fifthies (Fig. 4E), but are currently in a decaying state, if not completely
demolished.
Figure 4. A. Monteponi mine: “Laveria Calamine” (dressing plant) (1887), with potential to treat 100 tonn/day of bulk ore;
B. Monteponi mine: leaching tubs for Calamines before electrolysis (est. 1926); C. Monteponi mine: electrolytic cells (est.
1926); D. Monteponi mine: smelting furnaces for Zn cathodes (est. 1926); E. Monteponi mine: general view of the mine and
treatment plants (around 1950). Waste heaps in the foreground.
30Discovery and mining history of the “calamine“ in SW Sardinia (Italy)
31Maria Boni
3. Conclusions
On the whole, the „Calamine“ adventure was comparable for SW Sardinia to the „Gold Rush“, which had
affected countries like California and Alaska. It enriched a few, changed the life of many, and left a strong
mark on the territory. It was a solid dream that lasted more than hundred years, and allowed this small
Mediterranean island to enter the industrial revolution like most Northern European countries.
References
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Rendiconti Seminario Facoltà Scienze Università Cagliari Supplement, 7(2), 91-108.
Boni, M., Gilg, A., Aversa, G. and Balassone, G. 2003. The “Calamine” of SW Sardinia (Italy): geology, mineralogy and stable
isotope geochemistry of a supergene Zn-mineralisation. Economic Geology, 98(4), 731-748.
Fadda, A.F. 1997. Siti minelari in Sardegna. Coedisar, Cagliari, 72 pp.
Large, D. 2001. The geology of non-sulphide zinc deposits, an overview. Erzmetall, 54, 264-276.
Mezzolani S. and Simoncini A. 1993. Sardegna da salvare. Paesaggi e architetture delle miniere, Editrice Archivio Fotografico
Sardo, Nuoro, 212 pp.
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parlamentare d’inchiesta. Tipografia Eredi Botta, Firenze, 286.
Stara, P., Rizzo, R. and Tanca, G.A. 1996. Iglesiente-Arburese, miniere e minerali. Ente Minerario Sardo I, 238 pp.
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