Bottino Mine, Stazzema, Apuan Alps, Lucca Province, Tuscany, Italy
|Latitude & Longitude (WGS84):||43° 59' 29'' North , 10° 15' 30'' East|
|Latitude & Longitude (decimal):||43.99139,10.25833|
|Köppen climate type:||Csa : Hot-summer Mediterranean climate|
|Name(s) in local language(s):||Miniera del Bottino, Stazzema, Alpi Apuane, Lucca, Toscana, ItaIia|
The Bottino mine is widely famous for its Ag-rich minerals (1,612 kg of Ag per ton), as well as for its wonderfully cristallized specimens, mainly sulphides and sulphosalts. Its galleries are still partly praticable, even if difficult to reach and dangerous. Galleries entrance can be reached from Argentiera, near Ruosina, 2 km from Seravezza; galleries entrances can be reached by crossing the Vezza river and climbing the old incline on the northern slope of Monte Rocca; at the fork of two valleys the "Due Canali" adit is found(270 m); up into the right-hand valley galleries "Paoli" (385 m) and "Redola" (458 m) are reached, then the "Casello" and "Nuova", until the open pit on the vein outcropping is reached at 525 m (Senicioni area). The left-hand valley leads to the galleries "Breviglieri" (600 m) and "Rocca" (700 m). Other higher galleries can be reached by car from Camaiore to S. Anna di Stazzema, then 1 km walking along a trail through the pass between Mt. Rocca and Mt. Lieto.
Bottino's history fades back into centuries. Very likely it had been exploited by the Etruscans already, together with other Ag-bearing ore bodies in this area. The Roman continues until 1st century b. C., when all minerary activities were forbidden by law in the whole italian peninsula.
Public acts document minerary activities for the first time in XI century, when this area was disputed between the Counts of Corvaia and Vallecchia; in 1219 the territory was divided by agreement but the Republic of Lucca sized the mines in 1241 and kept them in spite of the opposition of the two Counts. A notarial deed of 1316 certifies that Bottino mine had become a personal property of Castruccio Castracani, Prince of Lucca; in 1348 the Republic of Pisa sized all mines of the Pietrasanta-Seravezza area, including Bottino, but exploitation was almost completely abandoned until 1515, when Florence definitely prevailed in Tuscany, also conquering these territories. Cosimo Medici the 1st, Grand Duke of Florence, reopened the Bottino mine in 1542, entrusting its management to Johann Ziegler (an hungarian) and to a group of experienced german foremen. A great quantity of documents in Florence public archives testify Cosimo's great effort to develope mining activities. The abandoned village of Gallena was completely remodeled to house the miners, bridge and smelting plants were built, new galleries excavated; a beautiful palace was built in Seravezza, as a residence for the Grand Duke when he visited the mines. Silver handicrafts made by using Bottino's material can be seen today in the Pitti museum in Florence. Cosimo's successors, Francesco the 1st and Ferdinando the 1st, continued the Bottino exploitation, but the mine was closed in 1592, due to decreasing production and difficulties caused by the presence of As and Sb. Various reports made during XVII and XVIII century describe the abandonment of the mine, in spite the persisting good conditions of adits and galleries. Attempts were made to start exploitation over again in 1697, by a joint venture company of italians and german, and at the end of XVIII century by british, but they all failed.
In 1829 a new Company was established and the mine reopened; after a short period of failure due to scarsity of financial means and very primitive exploitation method, the Company obtained very promising tests on materials from new assays and was reorganized in 1842, with the name of Compagnia Anonima del Bottino. Under the direction of Ing. Vegni and Ing. Blanchard, the mine fastly flourished and became the most important and better organized lead-silver mine in Italy; the production reached 1080 pounds of silver and 180.000 pounds of lead in 1849. It was visited and enthusiastically described many times by experts from all over.
Activities wew though interrupted in 1883 due to a heavy sags in silver and lead market prices; at that time 144 miners worked there, and the production was up to 570 tons of Ag-bearing lead per year. After almost 40 years of complete inactivity, works were started again in 1918 by a new Company, the Società Anonima Miniere dell'Argentiera, that for the first time unified the whole minerary area under one management. Until 1929 the mine was widely exploited again, also extending works to new and deeper areas, but activities ceased before 2nd World War. In this period, working conditions for miners were terrible.
After the war, some attempts have been made until 1969, but the mine is presently completely abandoned.
The older works, between XI and XVII century, were limited to outcroppings of the veins and consisted of trenches and small pits; only two galleries were opened ("Casello" and "Redola"), but mainly used for water drainage. Great works only started in 1836 by widening "Redola" transverse gallery and by exploiting the veins of both sides of it, with new galleries. The right-hand gallery was named "Sansoni" and the left one "Orsini"; these names have remained until today to designate the two main branches of the whole mine.
From these two new galleries, exploitation procedeed upwords to the outcropping, and two shafts were dug at both ends into particularly richly mineralized columns. A new gallery, deeper than "Redola", was opened to reach the bottom of the "Sansoni" shaft; its name is "Paoli", and it took ten years (1840-50) to escavate its 300 m, due to the presence of very hard schistous rocks. In 1851 was opened also Nuova tunnel.
The "Sansoni" and "Orsini" shafts were progressively widened forming large inclines along the veins; in 1855 a very rich area was discovered in the "Orsini" shaft, between "Redola" and "Paoli". A new shaft, the "Speranza" ("Hope") was started in 1859 between the other two, progressing from "Paoli" level; 125 m deep, the new shaft was connected in 1868 with a new 700 m long tunnel ("Due Canali") mainly used for water drainage and mineral quarrying. Later, the "Speranza" shaft was deepened 100 m below the "Due Canali" gallery. When the mine reopened, in 1918, the works were concentrated below the "Due Canali" tunnel, as the upper area was almost completely worked out. Four new levels was escavated from the "Speranza" shaft, new galleries ("Rocca") and shafts ("Locarni") were also escavated in a side area, but works had to be interrupted for financial reasons. Some of these works were completed after the war, and new assays attempted, but the general conditions of the mine are such that too big works would be required to start exploitation over again; the lower areas are permanently flooded, many landslides and collapses have chaotically filled the wider spaces. Moreover, the filling of used areas with sterile material has always been here a method for saving money by avoiding both trasportation and reinforcement. For all these reasons, the mine is very dangerous and it shouldn't be visited inside without a very expert guide.
The Bottino ore body is completely embedded in the paleozoic basement of Autoctono Unit and consists of a NW-SE belt of veins. The exploited veins dip W-SW and S at 50° to 70°, having variable extension and power. The main vein (usually called "Bottino vein") has been exploited from its outcropping (525 m) down to the "Venezia" level (174 m); its thickness locally reach 3 m. The vein system is crossed by faults and fractures, sometimes mineralized, in some cases corresponding to syn-metamorphic contacts.
The paleozoic rocks embedding the Bottino vein system belong to Filladi inferiori formation and Porphiroid and Porphyritic schists formation, the oldest formations of Apuane basement; they consists respectively of meta-greywackes and quartzitic phyllites and of metamorphosed rhyolite. Another typical rock, usually called "tormalinite", is widely present as columns along the veins; the miners called it "black quartz" due to its hardness and aspect, and used it as a guide horizon to ore.
The presence of this rock suggested a minerogenetic model for Bottino ore body:
1) Paleozoic: intensive volcanic activities formed the tourmalinite bodies, very rich in B and with metal concentrations (Ag, Au, Sn, W). [Stratabound tourmalinites (tourmaline, quartz, carbonates, rutile, apatite, zircon, chlorite, pyrrhotite), cutted through by quartz-sulfides veinlets, are conformable to the main Earliest Apenninic foliation. Tourmalinite fragments are also enclosed by the foliation.] 2) Oligocene-Miocene: metamorphic fluids mobilized metals and other elements, redepositing them in vein structures.
Veins have variable features: massive galena, with sphalerite and sulphosalts, in a quartz gangue; stockwork; concordant veinlets and lenses. Cavities are frequent along late fractures. Veins are heavily stretched, boudinaged and fractured; fragments of the embedding rocks are often surrounded by a sulphide matrix; veins of ductile sulphides (galena, meneghinite) flow through harder ones (pyrite, arsenopyrite).
The outstanding specimens for which Bottino mine is famous are found in three different locations:
1) cavities in veins. All the minerals of the veins can be found crystallized in cavities of variable sizes. In less rich areas cavities are smaller and mainly contain quartz and carbonates (siderite, calcite, dolomite), rarely rutile and pink to colorless apatite. Best cavities are located in sulphide-rich areas: they have elongated shapes similar to almonds or squashed pipes, and may even reach a length of 5 m with cross sections to 20x80 cm, though average smaller. Wonderful finds are reported by many authors, with mainly sphalerite (marmatite), galena xls up to 3 cm, boulangerite needles up to 13 cm, meneghinite xls up to 4 cm.
2) Fissures at the contacts of veins with hanging rock yield specimens found after the closing of the mine, even if mainly reports were made during works. They are discordant with the veins and with the embedding rocks' schistosity that is usually parallel to the veins. Their length is variable in size up to 2 m, width from a few mm to some cm; their walls may be either entirely lined with xls of assorted minerals or covered by crystallized siderite disseminated with sulphide xls. Fissures are mainly found in the porphiroidal formations; sometimes they group and intersect to form wider spaces wherein floating rock fragments, completely lined with xls can be found.
3) Quartz and dolomite veins in tourmalinite are very frequent at "Rocca" and "Breviglieri" level. Fissures and cavities often open inside the veins, yielding good xls of meneghinite, sphalerite, galena, pyrite, hairly boulangerite.
Silver is mainly present in galena and tetrahedrite (freibergite) and also forms Ag minerals such as pyrargyrite and argentopentlandite; nickel is also present in many minerals (ullmannite, gersdorffite, bottinoite). Paragenetic sequences essentially took place during Tertiary tectono-metamorphic event, perhaps except pyrrhotite, probably pre-metamorphic; pyrite and arsenopyrite formed first, later the Pb-Zn-Cu minerals, last the Ni ones.
61 valid minerals. 2 (TL) - type locality of valid minerals.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
66 - 145 Ma
|Cretaceous sedimentary rocks|